Answer: -4
Step-by-step explanation: I am guessing you meant ...99 + 2(8*3)...
3x + 99 + 2(8 x 3) = 135
3x + 99 + 2(24) = 135
3x + 99 +48 = 135
3x + 147 = 135
(3x + 147) - 147 = (135) - 147
3x = -12
(3x) ÷ 3 = (-12) ÷ 3
x = -4
Every triangle angles add up to 180.
So because one angle is 90 degrees you would subtract it from 180 to get 90 and then divide it by two which is 45 degrees.
Hope this helps, have a nice day! :)
It was an increase of 15%
X= -5 because you divide -5x by -5 to get x alone so you have to 25/-5 which is -5