Question

Consider the system of equations.

3x − y = 5,

2x + 3y = −15


Which value can the first equation be multiplied by to form opposite values on the y-term? A=-3 B= -2 C=2 D=3

The solution to the system of equations is .A= (-5,0) B= (5,0) C= (0,-5) D=(0,5)

Answer 1

D and C

Explanation:

Given the 2 equations

3x - y = 5 → (1)

2x + 3y = - 15 → (2)

Multiplying (1) by 3 and adding to (2) will eliminate the y- term

9x - 3y = 15 → (3)

Add (2) and (3) term by term to eliminate y

11x + 0 = 0

11x = 0 ⇒ x = 0

Substitute x = 0 into either of the 2 equations and solve for y

Substituting into (2)

2(0) + 3y = - 15

0 + 3y = - 15

3y = - 15 ( divide both sides by 3 )

y = - 5

solution is (0, - 5 )