Consider the sequence of steps to solve the equation:
5(x - 3) =
7x
2

Step 1 ⇒ 10(x - 3) = 7x
Step 2 ⇒ 10x - 30 = 7x
Step 3 ⇒ 3x - 30 = 0
Step 4 ⇒ 3x = 30
Step 5 ⇒ x = 10

Identify the property of equality which yields Step 3.

Question

Consider the sequence of steps to solve the equation:
5(x - 3) = 
7x
2

Step 1 ⇒ 10(x - 3) = 7x
Step 2 ⇒ 10x - 30 = 7x
Step 3 ⇒ 3x - 30 = 0
Step 4 ⇒ 3x = 30
Step 5 ⇒ x = 10

Identify the property of equality which yields Step 3.

Mercury · Answer

thoughts?

any ideas how they got from

10x - 30 = 7x

to

3x - 30 = 0?

the -30 is the same in both steps, so they only did something to the x-terms. did they add, subtract, divide, or multiply something from the equation in step 2?