Question

The sum of two numbers is 8. Two times the larger number plus four times the smaller number is 8. Find the numbers.

Answer 1

Answer: 12 and -4

Step-by-step explanation:

Assume the larger number is x and the smaller one is y.

In that case the relevant simultaneous equations are:

x + y = 8

2x + 4y = 8

Use substitution to find relative value of y:

x + y = 8

y = 8 - x

Use to solve equation:

2x + 4y = 8

2x + 4(8 - x) = 8

2x + 32 - 4x = 8

2x  - 4x= 8 - 32

-2x = -24

x = -24 / -2

x = 12

y = 8 - x

= 8 - 12

= -4