Question

What are x and y if 2y+x=−4 and y−x=−5?

Answer 1

2y + x = 4

y - x = - 5

2y + x = - 4

x. = -4 - 2y. [ putting it into equation 2]

y - x = - 5

y - (- 4 - 2y) = -5

y +4 + 2y = - 5

4 + 3 y = - 5

3 y. = -9

y. = - 3

putting it into equation 1

x = -4 -2y

= -4 -2(-3)

= -4 + 6

= 2

Answer 2

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

y - x= -5---------(b)

we will use elimination mthod to find x and y:

adding equation (a) and (b)

2y + x +(y-x)= -4 +(-5)

2y + x +y -x= -4-5

3y=-9

y = -9÷ 3= -3

hence, y = -3

now, put value of y in equation (b):

-3 -x = -5

-3+5=x

2 = x

hence, x=2