Question

sum of 2 numbers is 21 and subtractt to 7

Answer 1

Explanation :

•♦ Let the first numbers be 'x' and second is 'y'

•♦ So, the equation for sum is x + y = 21

•♦ and the equation for substraction is x - y = 7

By adding, equations 1st and 2nd

$\frac{x + y = 21}{x - y = 7} = 2x = 28 \\ so \: \: \: x = 14 \\ put \: x = 14 \: in \: equation \: x + y = 21 \\ x + y = 21 \\ 14 + y = 21 \\ y = 21 - 14 \\ y = 7$

So, the numbers are 14 and 7.