75=3(x-5) Distribute the 3 into the parenthesis, so: 3 times X and 3 times -5 Gives you 75=3x-15 What you do to one side of the = you can do to the other as long as its the same thing, so: 75+15=3x-15+15, the -15+15 will = 0 Gives you 90=3x Again, what you do to one side you can do the same to the other, so divide both sides by 3, so: 90/3 = (3x)/3 The 3's in the (3x)/3 can be thought of as 3/3 times x, and a number divided by itself is 1, leaving you with one x. Also, 90/3 = 30 so: x=30
3(4x-8)=36 Again we distribute the 3, multiplying it by everything inside the parenthesis 3 times 4x = 12x and 3 times -8 = -24. So: 12x-24=36 Add 24 to both sides to remove the -24 12x=60 divide by 12 on both sides, (12x) divided by 12 = 1x or just x, and 60 divided by 12 = 5, so: x=5
