Question

If P = –(x – 2), Q = –2(y + 1) and R = –x + 2y, find a, when P + Q + R = ax.

Answer 1

Given, P = –(x – 2), Q = –2(y + 1) and R = –x + 2y

Also given, P + Q + R = ax

On putting the values of P, Q and R on LHS, we get

–(x – 2) + [–2(y + 1)] + (–x + 2y) = ax

⇒ –x + 2 + (–2y – 2) – x + 2y = ax

⇒ –x + 2 – 2y – 2 – x + 2y = ax

On combining the like terms,

–x – x – 2y + 2y + 2 – 2 = ax

⇒ –2x = ax

By comparing LHS and RHS, we get

a = –2