The sum of two number is 1.Eight the 1st number is increased by five time the 2nd number is -13. Find the two numbers.

Answer 1

x = first number

y = second number

sum of two numbers is one

x+ y = 1

so y = 1-x

8 times the first number increased by 5 times the second number is -13

8x + 5y = -13

substitute 1-x for y in above equation:

8x + 5(1-x) = -13

8x + 5 - 5x = -13

3x = -18

x = -6

y = 1-x = 7