Combining Like Terms worksheet for 8th-9th - Free Printable

Let’s solve each problem step by step. We’re combining like terms — that means adding or subtracting numbers with numbers, and variables (like x or y) with the same variable.

---

#1: -7 + 13x + 2x + 8

First, group the x terms:
13x + 2x = 15x

Then group the numbers:
-7 + 8 = 1

So the simplified expression is:
→ 15x + 1

---

#2: 9 + 7y - 2 - 5y

Group the y terms:
7y - 5y = 2y

Group the numbers:
9 - 2 = 7

Simplified:
→ 2y + 7

---

#3: 2 + 3x - 4x + 6

Group the x terms:
3x - 4x = -1x (or just -x)

Group the numbers:
2 + 6 = 8

Simplified:
→ -x + 8 (or 8 - x — both are correct!)

---

#4: 5 + 2x + 2

Only one x term: 2x

Numbers: 5 + 2 = 7

Simplified:
→ 2x + 7

---

#5: 2(4x - 1) + x

First, distribute the 2:
2 × 4x = 8x
2 × (-1) = -2

Now rewrite:
8x - 2 + x

Combine x terms:
8x + x = 9x

Keep the -2

Simplified:
→ 9x - 2

---

#6: 6x + 2(x + 4)

Distribute the 2:
2 × x = 2x
2 × 4 = 8

Rewrite:
6x + 2x + 8

Combine x terms:
6x + 2x = 8x

Simplified:
→ 8x + 8

---

#7: 3(x + 5) - 10

Distribute the 3:
3 × x = 3x
3 × 5 = 15

Rewrite:
3x + 15 - 10

Combine numbers:
15 - 10 = 5

Simplified:
→ 3x + 5

---

#8: 15x - (x - 4)

Be careful! The minus sign in front of the parentheses applies to BOTH terms inside.

So:
-(x - 4) = -x + 4

Now rewrite the whole thing:
15x - x + 4

Combine x terms:
15x - x = 14x

Simplified:
→ 14x + 4

---

Final Answer:
#1: 15x + 1
#2: 2y + 7
#3: -x + 8
#4: 2x + 7
#5: 9x - 2
#6: 8x + 8
#7: 3x + 5
#8: 14x + 4