Question

multiply each equation by a constant that would help to eliminate the y terms.
2x - 5y = -21
3x - 3y = -18
what are the resulting equations?
○ 6x - 15y = -63
-15x + 15y = 90
○ 6x - 15y = 63
-15x + 15y = 90
○ 6x - 15y = -63
-15x + 15y = -90

Explanation:

Step1: Find LCM of y coefficients

The coefficients of $y$ are $-5$ and $-3$. The least common multiple (LCM) of 5 and 3 is 15. We need to make the $y$-terms opposites (15y and -15y) to eliminate them.

Step2: Multiply first equation by 3

Multiply $2x - 5y = -21$ by 3:
$3(2x - 5y) = 3(-21)$
$6x - 15y = -63$

Step3: Multiply second equation by -5

Multiply $3x - 3y = -18$ by -5 to get $+15y$:
$-5(3x - 3y) = -5(-18)$
$-15x + 15y = 90$

Answer:

6x−15y=−63
−15x+15y=90