You can perform the same operation (add, subtract, multiply, divide) on both sides of the equation. So you could add 3 to both sides like this:
ax + b = c + 3 + 3 ------------------- ax + b + 3 = c + 3 |
ax + b = c - b = c - b -------------------- ax = c - b |
ax c - b ---- = ----- a a |
c - b x = ----- a |
Example 1: |
3x + 5 = 17 <---- The original equation 3x + 5 = 17 - 5 -5 <---- Step 1: subtract 5 from both sides ------------ to remove it 3x = 12 3x = 12 --- --- <---- Step 2: divide both sides by 3 3 3 to remove the 3 x = 4 <---- The answer!!! |
Example 2: |
x/3 - 2 = 3 <---- The original equation x/3 - 2 = 3 + 2 +2 <---- Step 1: add 2 to both sides ---------------- to remove the -2 x/3 = 5 3x/3 = 3 x 5 <---- Step 2: multiply both sides by 3 to remove the 3 x = 15 <---- The answer!!! (3's cancelled) |
Example 3: |
35 - 3x = 14 <---- The original equation 35 - 3x = 14 -35 -35 <---- Step 1: subtract 35 from ------------------ both sides to remove it -3x = -21 -3x = -21 ---- ---- -3 -3 <---- Step 2: divide both sides by -3 to remove the -3 x = 7 <---- The answer!!! (remember, a negative divided by a negative is a positive) |