Solve by elimination

Question

the sum of two numbers is 1. five times the large number plus four times the smaller number is 20. find the numbers

Answer 1

"the sum of two numbers is 1. "

x + y = 1

"five times the large number plus four times the smaller number is 20."

5x + 4y = 20

to solve by elimination, multiply the 1st equation by 5 to get:

5x + 5y = 5

then subtract this from the 2nd equation to get:

-y = 15

So y = -15

From the 1st equation: x - 15 = 1

x = 16

CHECK by plugging the numbers into the second equation:

5(16) + 4(-15) = 80 - 60 = 20