3) $9x - 7=-7$\n5) $-4=\frac{r}{20}-5$\n7) $\frac{v + 9}{3}=8$\n9) $-9x + 1=-80$\n11) $-2=2+\frac{v}{4}$

3) $9x - 7=-7$\n5) $-4=\frac{r}{20}-5$\n7) $\frac{v + 9}{3}=8$\n9) $-9x + 1=-80$\n11) $-2=2+\frac{v}{4}$
Answer
Explanation:
Step1: Solve 9x - 7 = -7
Add 7 to both sides. $9x-7 + 7=-7 + 7$ $9x=0$ Divide both sides by 9. $x = 0$
Step2: Solve -4 = $\frac{r}{20}-5$
Add 5 to both sides. $-4 + 5=\frac{r}{20}-5 + 5$ $1=\frac{r}{20}$ Multiply both sides by 20. $r = 20$
Step3: Solve $\frac{v + 9}{3}=8$
Multiply both sides by 3. $v + 9=8\times3$ $v + 9 = 24$ Subtract 9 from both sides. $v=24 - 9$ $v = 15$
Step4: Solve -9x + 1 = -80
Subtract 1 from both sides. $-9x+1 - 1=-80 - 1$ $-9x=-81$ Divide both sides by -9. $x = 9$
Step5: Solve -2 = 2+$\frac{v}{4}$
Subtract 2 from both sides. $-2 - 2=2+\frac{v}{4}-2$ $-4=\frac{v}{4}$ Multiply both sides by 4. $v=-16$
Answer:
- $x = 0$
- $r = 20$
- $v = 15$
- $x = 9$
- $v=-16$