Answer:
x = -1
Explanation:
The first step is get rid of the numbers outside this (). So we will get
20+8x=9x+21 (multiplication) And we can get rid of one side of x by subtract 8x on both sides, an then we will get 20= x+21
And we can move the numbers to one side by subtract 21 on each side, and we will get -1=x
And rewrite it:
x = -1
That's the answer.