Question

The sum of two numbers is 13 and their difference is 5

Answer 1

x = 9 and y = 4

Explanation:

x + y =13 ----- ( equation 1)

x - y = 5 ----- ( equation 2)

From equation 1

x + y = 13

x = 13 - y

Substitute this in to equation 2

x - y = 5

( 13 - y) - y = 5

13 - y - y = 5

13 - 2y = 5

- 2y = 5 - 13

- 2y = - 8

divide both sides by -2

- 2y / -2 = - 8 / - 2

y = 4

equate this in to equation 1

x + y = 13

x + 4 = 13

x = 13 - 4

x = 9

Answer 2

let the numbers x and y

so x + y =13

x - y = 5

add two equations together

2x = 18

divide both side by 2

x = 9

sub in any equation

9 + y =13

y = 4

the numbers are 9 and 4

Explanation: