Answer: x = -7 and y = 35
Step-by-step explanation: STEPS USING SUBSTITUTION
y= -5x
y= - 7x - 14
consider the first equation. Add 5x to both sides.
y + 5x = 0
consider the second equation. Add 7x to both sides
y + 7x = -14
to solve a pair of equations using substitution, first solves one of the equations for one of the variables then substitute the result for that variable in the other equation. and so goes on