Since they’re complementary angles their total will be 90 degree so :
5x-2 + 3x+4 = 90
We add the like terms (valuables with valuables)
8x + 2 = 90
Move the 2 to the right side and change its sign
8x= 90-2
8x= 88
By dividing both sides by 8
X = 11
This is what I think so make sure it’s right and I hope this was helpful !