solve the equations using elimination

Question

solve the following equations using elimination x-2y=-1 and 2x+y=4

Answer 1

Elimination method

x-2y = -1

Multiple to each side by 2.

2x-4y = -2 ---------> (1)

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

To eliminate the x value subtract equation (2) from (1).

2x-4y = -2

2x+y = 4

(-)  (-)  (-)

________

-5y = -6

Divide to each side by negitive 5.

-5y/-5 = -6/-5

⇒ y = 6/5

Substitute the y value in (1).

2x-4*6/5 = -2

2x-24/5 = -2

Add 24/5 to each side.

2x = -2+24/5

2x = 14/5

Divide to each side by 2.

x = 14/10

⇒ x = 7/5

Solution x = 7/5,y = 6/5.