Question

if the sum and difference of two numbers is 35 and 7 respectively find them

Answer 1

let the numbers be X and y
X+ y= 35
x-y =7
adding both equation
2x=42
X=42/2
X = 21
and y =7

Answer 2

Let the two numbers be x and y.

Then :

x + y = 35..... 1

x - y = 7......... 2

Solving this simultaneously we have:

Subtracting 2 from 1 we have :

2y = 28

y = 28/2

Y = 14

Substitute this in 1

x + 14 = 35

x = 35 - 14

X = 21