This is the concept of algebra, in explaining the steps we use we proceed as follows;
5x-3(10-2x)=9(2x+6)
step1:
5x-3(10)-3(-2x)=9(2x)+9(6)
step2:
5x-30+6x=18x+54
next we want to put like terms together, begin by subtracting 5x from both sides:
The answer is D] Subtract 5x from both sides of the equation.