solve the system of equations

Question

-1x+3y=-4,  -2x-2y=-4

 

Answer 1

Elimination method

-x+3y = -4 -----------> (1)

-2x-2y = -4 ------------> (2)

Multiple equation (1) by 2.

-2x+6y = -8 ----------> (3)

To eliminate the x value subtract equation (3) from equation (2).

-2x-2y = -4

-2x+6y = -8

(+) (-)    (+)

_________

-8y = 4

Divide to each side by negitive 8.

-8y/-8 = 4/-8

y = -1/2

Substitute the y value in (1).

-x+3(-1/2) = -4

-x-3/2 = -4

Add 3/2 to each side.

-x-3/2+3/2 = -4+3/2

-x = -5/2

Cancell the signs to each side.

x  = 5/2

Solution of given equations x = 5/2, y = -1/2.