Question

Solve following pairs of linear equations using cross-multiplication method :
5x − 3y = 2
4x + 7y = −3

Answer 1

x = 5/47 ; y = -23/47

Explanation:

5x -  3y =  2 ------- (1)

4x + 7y = - 3 ------- (2)

(1) * 4 => 20x - 12y =  8

(2) * 5 => 20x + 35y = - 15

Subtracting ==> -47y = 23 (symbol changes causes 20x to be cancelled)

y = -23/47

Substituting value of y in (1), we get 5x + 3 (23/47) = 2

Solving we get x = 5/47