Question

Solve the following system of equations by substitution.
3y = 9
9y + 2x = -12
A. (1/3, 15/2)
B. (-1/3, - 15/2)
C. (8, 8)
D. (-39/2, 3)

Answer 1

\(y=9/3=3\)

Answer 2

take first equation, solve for y.
y=9/3=3

substitute in the second
9(9/3) + 2x = -12

solve for x ==> x= -39/2

so, it's D.

Answer 3

Thank your guys so much for your help! :)

Answer 4

Put \(y\) in the second equation and you get : \(2x+27=-12\)
So: \(x=-39/2\)
\((-39/2,3)\)