If all the angles add up to 90 degrees then you can set the equation 7x-9*2x=90
Simplify
9x-9=90
Plus 9 both sides
9x=99
Divide by 9 on both sides
X=11
Let's check
3m - 9 = 9+3m
collect like terms
3m -3m = 9 + 9
0m = 18
which is not possible, so it will not have any solutions
Answer:
50
Step-by-step explanation:




Plug 10 in for x.

Answer:
Step-by-step explanation:
There's no answer here. Because -6<21.