Question

The student who solved the equation made an error(s). Explain the error(s). State the correct solution.

(90−x)+2x+x=180
90−4x=180
4x=270
x=67.5

Answer 1

the negative sign before X in the bracket isn't supposed to affect the ones after the bracket

Explanation:

(90 - x) + 2x + x = 180

90 - x + 2x + x = 180

90 + 2x = 180

sub. 90 from both sides

2x = 90

x = 45