Question

Solve the following by elimination method 11x+15y+23=0 and 7x-2y-20=0

Answer 1

Let 11x + 15y + 23 = 0 be equation (1)
And 7x - 2y - 20 = 0 be equation (2)

Multiply equation (1) by 2:
22x + 30y + 46 = 0

Multiply equation (2) by 15:
105x - 30y - 300 = 0

Add equations (1) and (2):
22x + 105x + 30y - 30y + 46 - 300 = 0
127x - 254 = 0
127x = 254
x = 254/127
[x = 2]

Substitute x = 2 in equation (1) to find y:
11(2) + 15y + 23 = 0
22 + 15y + 23 = 0
15y + 45 = 0
15y = -45
y = -45/15
y = -3

Therefore, x = 2 and y = -3.