Question

5x + 4y = -5
-5x – 7y = -10

can somebody help me with that question ?

Answer 1

Add the two equations.
Did you do that?

Answer 2

\[\left( 5x +4y \right)+\left( -5x -7y \right)=-5+\left( -10 \right)\]
\[4y -7y =-15\]
\[-3y =-15\]
\[y =5\]
\[x =-5\]