Question

Solve the following by substitution method:
i) 4y = x and 4x + 3y = 19.

Answer 1

Given , 4y = x 
⇒ y = x/4
4x + 3y = 19
⇒4x + 3(x/4) = 19
⇒4x +3x/4 = 19
⇒(16x + 3x)/4 = 19
⇒19x/4 = 19
⇒ 19x = 19*4 = 76
⇒ x = 76/19 = 4
Now, y = x/4 = 4/4 = 1
Check : 4x+3y=19
⇒4(4) + 3(1) = 19
⇒16+3 = 19
⇒19=19
Therefore L.H.S = R.H.S .........