Solve each of the following systems of equations by using the method of cross multiplication:
3x + 2y + 25 = 0, 2x + y + 10 = 0.
We have,
3x + 2y + 25 = 0 …(i)
2x + y + 10 = 0 …(ii)
From equation (i), we get a1 = 3, b1 = 2 and c1 = 25
And from equation (ii), we get a2 = 2, b2 = 1 and c2 = 10
Using cross multiplication,
⇒
⇒
⇒
⇒ and
⇒ x = 5 and y = - 20
Thus, x = 5, y = - 20