Question

What is the value of x in the equation x – y = 30, when y = 15?

4
8
80
200

Answer 1

There are many ways of solving the set of equations x + y = 30 and x - y = 2 for x and y.

From x +y = 30 we get x = 30 - y

Now substitute this in the equation x - y = 2

30 - y - y = 2

-2y = -28

y = 14

As x = 30 - y = 30 - 14 = 16

The required solution of the set of equations is x = 16 and y = 14

Toodles~