Question

X + y = 0

5x + 3y = -8
Which of the following ordered pairs (x, y) satisfies the
system of equations above?
a) (4,-5)
b) (4, -4)
c) (-4,4)
d) (-3,3)

Answer 1

C

Explanation:

given the 2 equations

x + y = 0 → (1)

5x + 3y = - 8 → (2)

Rearrange (1) expressing x in terms of y by subtracting y from both sides

x = - y → (3)

Substitute x = - y into (2)

5(- y) + 3y = - 8, that is

- 5y + 3y = - 8

- 2y = - 8 ( divide both sides by - 2 )

y = 4

Substitute y = 4 into (3) for corresponding value of x

x = - y = - 4

Solution is (- 4, 4 ) → C