Question

Why is (3,-5) not a solution to -x+4y=-15

-2x-3y=-8

A) it satisfies the top equation but not the bottom
B) it’s satisfies the bottom equation but not the top
C) it doesn’t satisfy either the top or bottom equations
D) it satisfies both the top and bottom equations
Plz help !!!!!!

Answer 1

C) It doesn’t satisfy either the top or bottom equations.


When we plug them into the top equation:

`- 3 + 4( - 5) = - 15`
Simplify:

`- 3 + ( - 20) = - 15 \\ \\ - 23= - 15`
Because the statement of -23 = -15 is wrong, the solution pair is wrong for the top equation.


When we plug them into the bottom equation:

`- 2(3) - 3( - 5) = - 8`
Simplify:

`- 6 - ( - 15) = - 8 \\ \\ 9 = - 8`
9 = -8 is not a valid statement, so the pair doesn't satisfy both of the equations.