Solve:
By cross multiplication
(2 - 7x)(4 + 5x) = (3 + 7x)(1 - 5x)
⇒ 8 + 10x - 28x - 35x2 = 3 - 15x + 7x - 35x2
⇒ - 35x2 - 35x2 - 18x + 8x = 3 - 8
⇒ - 10x = - 5