Question

3(x + y) = 12

Answer 1

Answer:

B. -2.

Step-by-step explanation:

3(x + y) = 12

x/2 = 3

From the second equation

x = 2*3

x = 6.

Substitute for x in the first equation:

3(6 + y) = 12

18 + 3y = 12

3y = 12 - 18

3y = -6

y = -2.

Answer 2

Answer:

$\large\boxed{B)\ -2}$

Step-by-step explanation:

$\left\{\begin{array}{ccc}3(x+y)=12&(1)\\\\\dfrac{x}{2}=3&(2)\end{array}\right\\\\(2)\ \dfrac{x}{2}=3\qquad\text{multiply both sides by 2}\\\\2\!\!\!\!\diagup^1\cdot\dfrac{x}{2\!\!\!\!\diagup_1}=(2)(3)\\\\x=6\\\\\text{Put it to (1):}\\\\3(6+y)=12\qquad\text{divide both sides by 3}\\\\\dfrac{3\!\!\!\!\diagup^1(6+y)}{3\!\!\!\!\diagup_1}=\dfrac{12}{3}\\\\6+y=4\qquad\text{subtract 6 from both sides}\\\\6-6+y=4-6\\\\y=-2$