Question

twice a number minus a second number is -1. twice the second number added to three times the first number is 9. find the two numbers.

Answer 1

first number --- x
2nd number --- y

2x - y = -1
or
y = 2x+1

2y + 3x = 9
2(2x+1) + 3x = 9
4x + 2 + 3x = 9
7x = 7
x = 1
then y = 3

The first number is 1, and the second number is 3

check:
twice the first - second
= 2 - 3 = -1 , check!
twice the second added to three times the first
2(3) + 3(1)
= 9 , check!

Answer 2

qed