Question

Solve for $x$ and $y$: $y=2x+9$ and $7x+3y=-51$

• A. $-3$
• B. $-1$
• C. $2$
• D. $-4$

Answer 1

The correct option is A $-3$

$x=-6;y=-3$: Solve this system by substitution. Substitute the value given for $y$ in the first equation into the second equation. Then, distribute, combine like terms, and solve. Once you get a value for $x$, substitute it back into the first equation to obtain the value of $y$:

$y=2x+9$ $7x+3y=-51$

$7x+3(2x+9)-51$

$7x+6x+27=-51$

$13x+27=-51$

$13x=-78$

$x=-6$

$y=2x+9=2(-6)+9=-3$