how to do 2 step equations

Question

4x+5=45 is the question I need help on

Answer 1

4x + 5 = 45

What we need to do is isolate x. Step 1: move the constant to the other side. In this case, we do that but subtracting 5 to both sides:

4x + 5 - 5 = 45 - 5

4x = 40

 

Step two is divide both sides by 4:

4x / 4 = 40 / 4

x = 10

 

Check:

4 * 10 + 5 = 45

40 + 5 = 45

45 = 45

 

If you're familiar with the order of operations (parentheses, exponents, mult/div, add/sub), what you'll notice here is that we're reversing them in order to solve for x (that is, we add/sub before we touched the mult/div).

Answer 2

4x+5=45

subtract 5 from both sides

4x=40

divide both sides by 4

x=10

 

check:

4(10)+5=45

40+5=45

45=45