Answer:
C
Step-by-step explanation:
given the system of equations
5x + 3y = - 10 → (1)
- 20x - 7y = 15 → (2)
multiplying (1) by 4 and adding the result to (2) will eliminate x
20x + 12y = - 40 → (3)
add (2) and (3) term by term to eliminate x
(- 20x + 20x) + (- 7y + 12y) = 15 - 40
0 + 5y = - 25
5y = - 25 ( divide both sides by 5 )
y = - 5
substitute y = - 5 into either of the 2 original equations and solve for x
substituting into (1)
5x + 3(- 5) = - 10
5x - 15 = - 10 ( add 15 to both sides )
5x = 5 ( divide both sides by 5 )
x = 1
The solution is (1, - 5 )
