Answer:
Step 1
Because the number in front of the bracket is 1 and it is also affected by the negative sign(-),5 is supposed to be negative not positive because (negative by positive is negative)
And since the first step has an error in it,the remaining steps would also be wrong.
I hope that 2-1 means 21.
DE + EF = DF
4x + 10 + 21 = 9x - 15
4x + 31 = 9x - 15
31 = 9x - 4x - 15
31 = 5x - 15
46 = 5x
x = 9 1/5 = 9.2
You want 9x - 15
9*9.2 - 15
82.8 - 15
67.8 <<<<< answer.
If I have given the wrong meaning to 2-1 (which could mean 1) leave another note and I will correct my work.
According to a calculator, this is the answer: 0.1923076923. Hope this helped?