Quadratic Equations Annuity
1. Solve the quadratic equation $x^2 + 6x + 4 = 0$.
Use the quadratic formula $x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$ with $a=1$, $b=6$, $c=4$.
Calculate discriminant $\Delta = 6^2 - 4(1)(4) = 36 - 16 = 20$.
Find roots $x = \frac{-6 \pm \sqrt{20}}{2} = \frac{-6 \pm 2\sqrt{5}}{2} = -3 \pm \sqrt{5}$.
2. Solve $2x^2 + 10x + 45 = 29$.
Rewrite as $2x^2 + 10x + 45 - 29 = 0 \Rightarrow 2x^2 + 10x + 16 = 0$.
Divide by 2: $x^2 + 5x + 8 = 0$.
Calculate discriminant $\Delta = 5^2 - 4(1)(8) = 25 - 32 = -7$ (negative discriminant).
No real solutions; roots are complex: $x = \frac{-5 \pm i\sqrt{7}}{2}$.
3. Solve $x^2 - 16x + 20 = -8$.
Rewrite as $x^2 - 16x + 20 + 8 = 0 \Rightarrow x^2 - 16x + 28 = 0$.
Calculate discriminant $\Delta = (-16)^2 - 4(1)(28) = 256 - 112 = 144$.
Roots: $x = \frac{16 \pm 12}{2}$.
Hence $x = 14$ or $x = 2$.
4. Solve $4x^2 + 32x - 64 = 0$.
Divide entire equation by 4: $x^2 + 8x - 16 = 0$.
Discriminant $\Delta = 8^2 - 4(1)(-16) = 64 + 64 = 128$.
Roots: $x = \frac{-8 \pm \sqrt{128}}{2} = \frac{-8 \pm 8\sqrt{2}}{2} = -4 \pm 4\sqrt{2}$.
5. Solve $x^2 - 25x + 3x - 121 = 22x$.
Combine like terms: $x^2 - 22x - 121 = 22x$.
Bring all terms to one side: $x^2 - 22x - 121 - 22x = 0 \Rightarrow x^2 - 44x - 121 = 0$.
Discriminant $\Delta = (-44)^2 - 4(1)(-121) = 1936 + 484 = 2420$.
Roots: $x = \frac{44 \pm \sqrt{2420}}{2} = 22 \pm \sqrt{605}$.
6. Solve $x^2 + 67x = 0$.
Factor: $x(x + 67) = 0$.
Solutions: $x = 0$ or $x = -67$.
7. Solve $x^2 + 45x = -46$.
Rewrite: $x^2 + 45x + 46 = 0$.
Discriminant $\Delta = 45^2 - 4(1)(46) = 2025 - 184 = 1841$.
Roots: $x = \frac{-45 \pm \sqrt{1841}}{2}$.
8. Solve $2x^2 + 25 = 26x$.
Bring all to one side: $2x^2 - 26x + 25 = 0$.
Discriminant $\Delta = (-26)^2 - 4(2)(25) = 676 - 200 = 476$.
Roots: $x = \frac{26 \pm \sqrt{476}}{4}$.
II. Use annuity formulas to solve the problems.
1. Robert: $P=4000$ (monthly), $r=5\% = 0.05$ annually, $t=36$ years 4 months = $36 + \frac{4}{12} = 36.3333$ years.
Monthly interest rate $i = \frac{0.05}{12} \approx 0.0041667$.
Number of payments $n = 36.3333 \times 12 = 436$.
Future Value (FV) formula: $$FV = P \times \frac{(1+i)^n - 1}{i}$$
Calculate: $$FV = 4000 \times \frac{(1.0041667)^{436} - 1}{0.0041667}$$.
Present Value (PV) formula: $$PV = P \times \frac{1 - (1+i)^{-n}}{i}$$
Calculate: $$PV = 4000 \times \frac{1 - (1.0041667)^{-436}}{0.0041667}$$.
2. Philip: $P=300$, $r=6.5\% = 0.065$ annually, $t=16$ years.
Monthly interest rate $i = \frac{0.065}{12} \approx 0.0054167$.
Number of payments $n = 16 \times 12 = 192$.
Future Value (FV): $$FV = 300 \times \frac{(1.0054167)^{192} - 1}{0.0054167}$$.
Present Value (PV): $$PV = 300 \times \frac{1 - (1.0054167)^{-192}}{0.0054167}$$.
III. Missing values refer to previous questions or annuity amounts; if any specific missing is required, please specify.