Solving Inequalities
1. Problem: Solve each inequality below, then match to the graph that represents its solution set.
1. Solve $x + 11 > 16$:
Subtract 11 from both sides:
$$x + 11 - 11 > 16 - 11$$
$$x > 5$$
The solution is all $x$ greater than 5, so on the number line this is an arrow pointing right starting just above 5.
2. Solve $x - 6 < 1$:
Add 6 to both sides:
$$x - 6 + 6 < 1 + 6$$
$$x < 7$$
This means all $x$ less than 7.
3. Solve $x + 2 \leq -3$:
Subtract 2 from both sides:
$$x + 2 - 2 \leq -3 - 2$$
$$x \leq -5$$
This is all $x$ less than or equal to -5.
4. Solve $x + 3 \geq 1$:
Subtract 3:
$$x + 3 - 3 \geq 1 - 3$$
$$x \geq -2$$
5. Solve $x - 1 < -7$:
Add 1:
$$x - 1 + 1 < -7 + 1$$
$$x < -6$$
Match graphs:
- For $x > 5$ (1), the graph must show values greater than 5. Among given graphs c and e go right from 0 and 0 respectively, so c which goes 0 to 8 arrow right matches.
- For $x < 7$ (2), all less than 7, but upper bound is near 8; matches graph e (arrow left near 8).
- For $x \leq -5$ (3), less than or equal to -5, matches a (arrow left -8 to 0).
- For $x \geq -2$ (4), greater or equal to -2, matches b (arrow right -4 to 4).
- For $x < -6$ (5), less than -6, matches d (arrow right from -8 to 0 but near -8, maybe a typo, so matches a better).
6. Solve $d - 5 \leq 1$:
Add 5:
$$d \leq 6$$
Graph: arrow left at 6.
7. Solve $s + 9 < 8$:
Subtract 9:
$$s < -1$$
8. Solve $a - 7 \geq -13$:
Add 7:
$$a \geq -6$$
9. Solve $w - 1 < 4$:
Add 1:
$$w < 5$$
10. Solve $4 \geq k + 3$:
Subtract 3:
$$1 \geq k$$
$$k \leq 1$$
11. Solve $-9 \leq b - 4$:
Add 4:
$$-5 \leq b$$
$$b \geq -5$$
12. Solve $-2 \geq x + 4$:
Subtract 4:
$$-6 \geq x$$
$$x \leq -6$$
13. Solve $2y < y + 2$:
Subtract $y$:
$$2y - y < y + 2 - y$$
$$y < 2$$
14. Define variable $n$. "A number decreased by 10 is greater than -5":
$$n - 10 > -5$$
$$n > 5$$
15. Variable $m$. "A number increased by 1 is less than 9":
$$m + 1 < 9$$
$$m < 8$$
16. Variable $x$. "Seven more than a number is less than or equal to -18":
$$x + 7 \leq -18$$
$$x \leq -25$$
17. Variable $y$. "Twenty less than a number is at least 15":
$$y - 20 \geq 15$$
$$y \geq 35$$
18. Variable $a$. "A number plus 2 is at most 1":
$$a + 2 \leq 1$$
$$a \leq -1$$
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Second Set:
1. Solve $-8 \geq x - 15$:
Add 15:
$$7 \geq x$$
$$x \leq 7$$
2. Solve $4x + 3 < 5x$:
Subtract $4x$:
$$3 < x$$
$$x > 3$$
3. Solve $8x > 7x - 4$:
Subtract $7x$:
$$x > -4$$
4. Solve $12 + x \leq 9$:
Subtract 12:
$$x \leq -3$$
Match graphs:
- $x \leq 7$ (1) matches b (0 to 8 arrow right).
- $x > 3$ (2) matches b from 0 to 8 arrow right starting above 3.
- $x > -4$ (3) matches a (-6 to 2 arrow right from just above -4).
- $x \leq -3$ (4) matches d (0 to 8 arrow left from 0, but 0 to 8 left arrow isn't below -3, best match is c left from -8 to 0).
5. Solve $r - (-5) > -2$:
$$r + 5 > -2$$
Subtract 5:
$$r > -7$$
6. Solve $3x + 8 \geq 4x$:
Subtract $3x$:
$$8 \geq x$$
$$x \leq 8$$
7. Solve $n - 2.5 \geq -5$:
Add 2.5:
$$n \geq -2.5$$
8. Solve $1.5 < y + 1$:
Subtract 1:
$$0.5 < y$$
$$y > 0.5$$
9. Solve $z + 3 > \frac{2}{3}$:
Subtract 3:
$$z > -\frac{7}{3}$$
10. Solve $\frac{1}{2} \leq c - \frac{3}{4}$:
Add $\frac{3}{4}$:
$$\frac{1}{2} + \frac{3}{4} \leq c$$
$$\frac{5}{4} \leq c$$
$$c \geq 1.25$$
11. "The sum of a number and 17 is no less than 26":
$$n + 17 \geq 26$$
$$n \geq 9$$
12. "Twice a number minus 4 is less than three times the number":
Let $x$ be the number:
$$2x - 4 < 3x$$
Subtract $2x$:
$$-4 < x$$
$$x > -4$$
13. "Twelve is at most a number decreased by 7":
$$12 \leq x - 7$$
Add 7:
$$19 \leq x$$
$$x \geq 19$$
14. "Eight plus four times a number is greater than five times the number":
$$8 + 4x > 5x$$
Subtract $4x$:
$$8 > x$$
$$x < 8$$
15. Plane altitude problem:
Plane altitude = $5.8$ miles
Troposphere depth = $8.6$ miles
Remaining height before leaving troposphere:
$$8.6 - 5.8 = 2.8$$
16. Soil cushion problem:
Topsoil depth = 30 cm
Bush hole depth = 18 cm
Current cushion = 8 cm
Remaining depth for cushion:
$$30 - 18 = 12$$ cm total cushion allowed
Remaining cushion addition:
$$12 - 8 = 4$$ cm
Final answers summarized:
"q_count":16