Question

5x+ (3x-4)- (2x-9) =45

Answer 1

5x + (3x-4) - (2x-9) = 45
5x+3x-4-2x+9 = 45
5x+3x-2x = 45+4-9
6x = 40
x = 40/6
x = 20/3

Answer 2

$5x + (3x - 4) - (2x - 9) = 45 \\ 5x + 3x - 4 - 2x + 9 = 45 \\ 5x + 3x - 2x = 45 + 4 - 9 \\ 6x = 40 \\ x = \frac{40}{6} = \frac{20}{3}$