Question

2x+y=11-1
y=3x-9-2
subtitute ecuacion 2 in 1
2x+3x-9=11

Answer 1

Let's solve it step by step and fix the small arithmetic mistakes.

Original system (as written):
1) 2x + y = 11 − 1
2) y = 3x − 9 − 2

Simplify each equation:
1) 2x + y = 10 (because 11 − 1 = 10)
2) y = 3x − 11 (because 3x − 9 − 2 = 3x − 11)

Substitute equation 2 into equation 1:
2x + (3x − 11) = 10
5x − 11 = 10
5x = 21
x = 21/5 = 4.2

Find y:
y = 3x − 11 = 3*(21/5) − 11 = 63/5 − 55/5 = 8/5 = 1.6

Solution: x = 21/5, y = 8/5.