Question

If 2x + y = 23 and 4x – y = 19, then find the value of 5y − 2x .

Answer 1

The given equations are

2x + y = 23 ...(i)

4x – y = 19 ...(ii)

On adding (i) and (ii), we get

6x = 42 $\Rightarrow$ x = 7 On putting x = 7 in (i), we get
14 + y = 23 $\Rightarrow$ y = 9

Now,

5y − 2x = 5 $\times$ 9 − 2 $\times$ 7=31