Question

1. - 6xy + y2 + 9zx = 0
2. x + 2y = 7
3. a +7<0
Which of the following are linear equations?​

Answer 1

3x+2y=7

4x+y=6⇒y=6−4x

placing in equation (1)

3x+2(6−4x)=7

3x+12−8x=7⇒−5x+12=7

−5x=7−12⇒−5x=−5

x=1

∴ y = 6 - 4×1=2

∴ x = 1, y = 2