Indices Simplify Solve Efec4A
1. Simplify the following expressions involving indices.
(i) Simplify $a^2 (2a^{-1})^2$:
- Use the power of a product rule: $(xy)^n = x^n y^n$.
- $(2a^{-1})^2 = 2^2 (a^{-1})^2 = 4a^{-2}$.
- Multiply by $a^2$: $a^2 \times 4a^{-2} = 4a^{2 + (-2)} = 4a^0 = 4$.
(ii) Simplify $2^n \times 8^{2n}$:
- Express 8 as $2^3$: $8^{2n} = (2^3)^{2n} = 2^{6n}$.
- Multiply powers with the same base: $2^n \times 2^{6n} = 2^{n + 6n} = 2^{7n}$.
(iii) Simplify $5a^4 b^3 (a^2 b^5)^2$:
- Apply power to each factor: $(a^2)^2 = a^4$, $(b^5)^2 = b^{10}$.
- Expression becomes $5a^4 b^3 \times a^4 b^{10} = 5a^{4+4} b^{3+10} = 5a^8 b^{13}$.
(iv) Simplify $\frac{x^4 (y^2 z^3)^4}{(x^2 z^{-5})^2}$:
- Expand numerator: $(y^2)^4 = y^8$, $(z^3)^4 = z^{12}$, so numerator is $x^4 y^8 z^{12}$.
- Expand denominator: $(x^2)^2 = x^4$, $(z^{-5})^2 = z^{-10}$, so denominator is $x^4 z^{-10}$.
- Divide powers: $\frac{x^4 y^8 z^{12}}{x^4 z^{-10}} = y^8 z^{12 - (-10)} = y^8 z^{22}$.
(v) Simplify $\frac{9^0 \times 81 \times 32^2}{3^8 \times 16^3}$:
- $9^0 = 1$.
- Express bases as powers of 3 and 2: $81 = 3^4$, $32 = 2^5$, $16 = 2^4$.
- Numerator: $1 \times 3^4 \times (2^5)^2 = 3^4 \times 2^{10}$.
- Denominator: $3^8 \times (2^4)^3 = 3^8 \times 2^{12}$.
- Divide: $3^{4-8} \times 2^{10-12} = 3^{-4} \times 2^{-2} = \frac{1}{3^4} \times \frac{1}{2^2} = \frac{1}{81 \times 4} = \frac{1}{324}$.
(vi) Simplify $\frac{8^2 \times 4^4}{32 \times 16^3}$:
- Express bases as powers of 2: $8=2^3$, $4=2^2$, $32=2^5$, $16=2^4$.
- Numerator: $(2^3)^2 \times (2^2)^4 = 2^6 \times 2^8 = 2^{14}$.
- Denominator: $2^5 \times (2^4)^3 = 2^5 \times 2^{12} = 2^{17}$.
- Divide: $2^{14-17} = 2^{-3} = \frac{1}{8}$.
(vii) Simplify $\frac{15 x^{-2}}{x}$:
- $x^{-2} / x = x^{-2 - 1} = x^{-3}$.
- Expression: $15 x^{-3} = \frac{15}{x^3}$.
(viii) Simplify $\frac{(9x)^{-3}}{3x^3}$:
- $(9x)^{-3} = 9^{-3} x^{-3} = (3^2)^{-3} x^{-3} = 3^{-6} x^{-3}$.
- Denominator: $3 x^3$.
- Divide: $\frac{3^{-6} x^{-3}}{3 x^3} = 3^{-6 - 1} x^{-3 - 3} = 3^{-7} x^{-6} = \frac{1}{3^7 x^6}$.
(ix) Simplify $\frac{2a^2 b^3}{(2ab)^{-2}}$:
- Denominator: $(2ab)^{-2} = 2^{-2} a^{-2} b^{-2}$.
- Expression: $2 a^2 b^3 \times 2^{2} a^{2} b^{2} = 2^{1+2} a^{2+2} b^{3+2} = 2^3 a^4 b^5 = 8 a^4 b^5$.
(x) Simplify $\frac{25^{3n} \times 125}{625^n}$:
- Express bases as powers of 5: $25=5^2$, $125=5^3$, $625=5^4$.
- Numerator: $(5^2)^{3n} \times 5^3 = 5^{6n} \times 5^3 = 5^{6n + 3}$.
- Denominator: $(5^4)^n = 5^{4n}$.
- Divide: $5^{6n + 3 - 4n} = 5^{2n + 3}$.
(xi) Simplify $\sqrt{\frac{2}{7} \times \frac{9}{4} a^4}$:
- Multiply inside the root: $\frac{2}{7} \times \frac{9}{4} = \frac{18}{28} = \frac{9}{14}$.
- So expression is $\sqrt{\frac{9}{14} a^4} = \sqrt{\frac{9}{14}} \times \sqrt{a^4} = \frac{3}{\sqrt{14}} a^2$.
(xii) Simplify $(\frac{2}{5})^{-3} \times \frac{32}{25}$:
- $(\frac{2}{5})^{-3} = (\frac{5}{2})^{3} = \frac{125}{8}$.
- Multiply: $\frac{125}{8} \times \frac{32}{25} = \frac{125 \times 32}{8 \times 25} = \frac{4000}{200} = 20$.
2. Simplify expressions with fractional and negative indices.
(i) $8^{1/3} = (2^3)^{1/3} = 2^{3 \times \frac{1}{3}} = 2^1 = 2$.
(ii) $9^{3/2} = (3^2)^{3/2} = 3^{2 \times \frac{3}{2}} = 3^3 = 27$.
(iii) $32^{-3/5} = (2^5)^{-3/5} = 2^{5 \times (-3/5)} = 2^{-3} = \frac{1}{8}$.
(iv) $49^{-3/2} = (7^2)^{-3/2} = 7^{2 \times (-3/2)} = 7^{-3} = \frac{1}{343}$.
(v) $(\sqrt[3]{5})^{10} = 5^{\frac{1}{3} \times 10} = 5^{10/3}$.
(vi) $(\frac{16}{81})^{-1/4} = (\frac{2^4}{3^4})^{-1/4} = (\frac{2}{3})^{-1} = \frac{3}{2}$.
(vii) Simplify $5^{n+1} \times 25^n \div 125^{(3n-1)/3}$:
- Express bases as powers of 5: $25=5^2$, $125=5^3$.
- Expression: $5^{n+1} \times (5^2)^n \div (5^3)^{(3n-1)/3} = 5^{n+1} \times 5^{2n} \div 5^{3n-1} = 5^{n+1+2n - (3n -1)} = 5^{n+1+2n - 3n +1} = 5^{2}$.
(viii) Simplify $\frac{(32^{5/3} (2/3))^{-2}}{\sqrt{5/16}}$:
- $32 = 2^5$, so $32^{5/3} = (2^5)^{5/3} = 2^{25/3}$.
- Numerator inside parentheses: $2^{25/3} \times \frac{2}{3}$.
- Raise to $-2$: $(2^{25/3} \times \frac{2}{3})^{-2} = 2^{-50/3} \times (\frac{2}{3})^{-2} = 2^{-50/3} \times (\frac{3}{2})^{2} = 2^{-50/3} \times \frac{9}{4}$.
- Denominator: $\sqrt{\frac{5}{16}} = \frac{\sqrt{5}}{4}$.
- Expression: $\frac{2^{-50/3} \times \frac{9}{4}}{\frac{\sqrt{5}}{4}} = 2^{-50/3} \times 9 \times \frac{1}{\sqrt{5}} = \frac{9}{\sqrt{5}} 2^{-50/3}$.
(ix) Simplify $\frac{2^{2n+1} 3^{n+10}}{3^{n+1} 2^{n-1}}$:
- Divide powers with same base: $2^{2n+1 - (n-1)} = 2^{n+2}$.
- $3^{n+10 - (n+1)} = 3^{9}$.
- Expression: $2^{n+2} \times 3^{9}$.
(x) Simplify $\frac{3^{n+3}}{3^{n-1}} \div \frac{9^{n+1}}{3^{n-1}}$:
- First fraction: $3^{n+3 - (n-1)} = 3^{4}$.
- Second fraction: $\frac{9^{n+1}}{3^{n-1}} = \frac{(3^2)^{n+1}}{3^{n-1}} = \frac{3^{2n+2}}{3^{n-1}} = 3^{n+3}$.
- Division: $3^{4} \div 3^{n+3} = 3^{4 - (n+3)} = 3^{1 - n}$.
(xi) Simplify $\frac{81 \times 27^{2n}}{3^{5n+1}}$:
- Express bases as powers of 3: $81=3^4$, $27=3^3$.
- Numerator: $3^4 \times (3^3)^{2n} = 3^4 \times 3^{6n} = 3^{4+6n}$.
- Divide by denominator: $3^{4+6n - (5n+1)} = 3^{n+3}$.
(xii) Simplify $\frac{32^{n+2}}{2^n 4^{n+2}}$:
- Express bases as powers of 2: $32=2^5$, $4=2^2$.
- Numerator: $(2^5)^{n+2} = 2^{5n + 10}$.
- Denominator: $2^n \times (2^2)^{n+2} = 2^n \times 2^{2n + 4} = 2^{3n + 4}$.
- Divide: $2^{5n + 10 - (3n + 4)} = 2^{2n + 6}$.
3. Solve the following equations for the unknown.
(i) Solve $4^{3n} = 32$:
- Express bases as powers of 2: $4=2^2$, $32=2^5$.
- Equation: $(2^2)^{3n} = 2^5 \Rightarrow 2^{6n} = 2^5$.
- Equate exponents: $6n = 5 \Rightarrow n = \frac{5}{6}$.
(ii) Solve $3^{7n - 15} = (\frac{1}{3})^{y + 3}$:
- Rewrite right side: $(\frac{1}{3})^{y+3} = 3^{-(y+3)}$.
- Equate exponents: $7n - 15 = -(y + 3)$.
- Rearranged: $7n - 15 = -y - 3$.
(iii) Solve $4^{3n + 6} = 1$:
- $1 = 4^0$.
- Equate exponents: $3n + 6 = 0 \Rightarrow n = -2$.
(iv) Solve $4 \times 2^{6 - 3n} = 32$:
- Express 4 and 32 as powers of 2: $4=2^2$, $32=2^5$.
- Equation: $2^2 \times 2^{6 - 3n} = 2^5 \Rightarrow 2^{2 + 6 - 3n} = 2^5$.
- Exponents: $8 - 3n = 5 \Rightarrow -3n = -3 \Rightarrow n = 1$.
(v) Solve $8^{3x - 9} - 12 = 500$:
- Add 12: $8^{3x - 9} = 512$.
- Express 8 and 512 as powers of 2: $8=2^3$, $512=2^9$.
- Equation: $(2^3)^{3x - 9} = 2^9 \Rightarrow 2^{9x - 27} = 2^9$.
- Equate exponents: $9x - 27 = 9 \Rightarrow 9x = 36 \Rightarrow x = 4$.
(vi) Solve $81^{x+1} \times 9^{1+4x} = 35^x$:
- Express 81 and 9 as powers of 3: $81=3^4$, $9=3^2$.
- Left side: $3^{4(x+1)} \times 3^{2(1+4x)} = 3^{4x + 4 + 2 + 8x} = 3^{12x + 6}$.
- Right side: $35^x$ (cannot express as power of 3).
- Equation: $3^{12x + 6} = 35^x$.
- This equation cannot be solved with integer exponents; requires logarithms.
(vii) Solve $10 \times 3^{x+1} = 243$:
- Express 243 as $3^5$.
- Divide both sides by 10: $3^{x+1} = \frac{243}{10}$.
- Take logarithm base 3: $x + 1 = \log_3 \frac{243}{10}$.
- $x = \log_3 \frac{243}{10} - 1$.
(viii) Solve $2 \times 25^{x-1} - 7 = 243$:
- Add 7: $2 \times 25^{x-1} = 250$.
- Divide by 2: $25^{x-1} = 125$.
- Express bases as powers of 5: $25=5^2$, $125=5^3$.
- Equation: $(5^2)^{x-1} = 5^3 \Rightarrow 5^{2x - 2} = 5^3$.
- Equate exponents: $2x - 2 = 3 \Rightarrow 2x = 5 \Rightarrow x = \frac{5}{2}$.
(ix) Solve $(3.14)^{p-1} + 11 = 12$:
- Subtract 11: $(3.14)^{p-1} = 1$.
- Since any number to the power 0 is 1, $p - 1 = 0 \Rightarrow p = 1$.
Final answers:
(i) $4$
(ii) $2^{7n}$
(iii) $5a^8 b^{13}$
(iv) $y^8 z^{22}$
(v) $\frac{1}{324}$
(vi) $\frac{1}{8}$
(vii) $\frac{15}{x^3}$
(viii) $\frac{1}{3^7 x^6}$
(ix) $8 a^4 b^5$
(x) $5^{2n + 3}$
(xi) $\frac{3}{\sqrt{14}} a^2$
(xii) $20$
2(i) $2$
2(ii) $27$
2(iii) $\frac{1}{8}$
2(iv) $\frac{1}{343}$
2(v) $5^{10/3}$
2(vi) $\frac{3}{2}$
2(vii) $5^2 = 25$
2(viii) $\frac{9}{\sqrt{5}} 2^{-50/3}$
2(ix) $2^{n+2} 3^9$
2(x) $3^{1-n}$
2(xi) $3^{n+3}$
2(xii) $2^{2n + 6}$
3(i) $n=\frac{5}{6}$
3(ii) $7n - 15 = -(y + 3)$
3(iii) $n = -2$
3(iv) $n=1$
3(v) $x=4$
3(vi) No simple solution without logarithms
3(vii) $x = \log_3 \frac{243}{10} - 1$
3(viii) $x=\frac{5}{2}$
3(ix) $p=1$