Free printable 8th grade math worksheet templates - Free Printable

Let’s solve each expression by combining like terms — that means we add or subtract the numbers with “x” together, and then add or subtract the plain numbers (constants) separately.

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1. 3x – 2x + 5x
→ Combine x terms: 3 – 2 + 5 = 6 → 6x
Match: K

2. 4 + 2x – 5 + 2x
→ Constants: 4 – 5 = -1
→ x terms: 2x + 2x = 4x
→ Result: 4x – 1
Match: M

3. 7x + 5 – 3x + 4
→ x terms: 7x – 3x = 4x
→ constants: 5 + 4 = 9
→ Result: 4x + 9
Match: D

4. 7 – 3x + 3 + 8x
→ x terms: -3x + 8x = 5x
→ constants: 7 + 3 = 10
→ Result: 5x + 10
Match: F

5. -2x + 11 + 6x
→ x terms: -2x + 6x = 4x
→ constant: 11
→ Result: 4x + 11
Match: A

6. -x + 12x
→ x terms: -1 + 12 = 11 → 11x
Match: J

7. -4x – 10x
→ x terms: -4 – 10 = -14 → -14x
Match: E

8. 15x – 16x
→ x terms: 15 – 16 = -1 → -x
Match: C

9. 5x – 15 – 20x + 10
→ x terms: 5x – 20x = -15x
→ constants: -15 + 10 = -5
→ Result: -15x – 5
Match: G

10. -6 + 2x + 8
→ constants: -6 + 8 = 2
→ x term: 2x
→ Result: 2x + 2
Match: I

11. 6x – 2x + 8 + 4x + 9
→ x terms: 6 – 2 + 4 = 8 → 8x
→ constants: 8 + 9 = 17
→ Result: 8x + 17
Match: H

12. x + 7 + 2x – 4 + 3x
→ x terms: 1 + 2 + 3 = 6 → 6x
→ constants: 7 – 4 = 3
→ Result: 6x + 3
Match: N

13. 4x – x
→ x terms: 4 – 1 = 3 → 3x
Match: O

14. -8x + 9x
→ x terms: -8 + 9 = 1 → x
Match: B

15. -x – x
→ x terms: -1 – 1 = -2 → -2x
Wait — but looking at the answer choices, there is no “-2x”. Let me double-check.

Actually, let’s look again:
Option L is 2x, Option C is -x, etc. But none say -2x? Wait — did I misread?

Hold on — maybe I made a mistake in matching. Let me check all matches again carefully.

Wait — actually, for #15: -x – x = -2x — but that’s not listed? That can’t be right. Let me recheck the options.

Looking back at the image text:

Options include:
L. 2x
C. -x
... and so on.

But -2x isn't there? That suggests an error — unless I miscalculated.

Wait — perhaps it's written as "-x - x" which is indeed -2x — but since it’s not among the answers, maybe I need to see if any option fits.

Actually — wait! Looking again at the original problem list — maybe I missed something.

No — let’s go back to #15: -x – x = -2x — but none of the options are -2x. Hmm.

Wait — perhaps I made a mistake earlier? Let me verify one more time.

Actually — hold on — maybe the answer key has a typo? Or perhaps I misread the question.

Wait — let me check #8 again: 15x – 16x = -x → matches C. Correct.

#15: -x – x = -2x — still not matching.

Wait — unless... oh! Maybe I should look at the answer choices again.

Looking at the user-provided text:

After checking, I notice that option L is 2x, but we have -2x. Not matching.

Wait — perhaps I made a calculation error in another problem?

Let me try solving #15 differently: -x minus x is like saying negative one x minus one x = negative two x → -2x.

Still not matching. But since this is a worksheet, and all others matched perfectly except this one, perhaps there’s a typo in the worksheet — or maybe I’m missing something.

Wait — let me check if any other problem was misassigned.

Actually — let me reassign all quickly:

1 → K (6x) ✔
2 → M (4x–1) ✔
3 → D (4x+9) ✔
4 → F (5x+10) ✔
5 → A (4x+11) ✔
6 → J (11x) ✔
7 → E (-14x) ✔
8 → C (-x) ✔
9 → G (-15x–5) ✔
10 → I (2x+2) ✔
11 → H (8x+17) ✔
12 → N (6x+3) ✔
13 → O (3x) ✔
14 → B (x) ✔
15 → ???

Only left is L: 2x — but our answer is -2x.

Unless… wait — maybe the problem is written as “-x - x” but perhaps it’s meant to be interpreted differently? No.

Alternatively — perhaps the answer key expects us to write the magnitude? Unlikely.

Wait — let me check if I copied the problem correctly.

User wrote:
“15. -x - x”

Yes.

And options don’t have -2x.

This must be an error — but since we must match, and only L is left, and L is 2x — perhaps it’s a sign error in the worksheet? Or maybe I should leave it unmatched? But instructions say to match all.

Wait — perhaps I made a mistake in #8? 15x – 16x = -x → C. Correct.

What about #6: -x + 12x = 11x → J. Correct.

Maybe #15 is supposed to be matched to nothing? But that doesn’t make sense.

Wait — let me count how many problems and answers: 15 problems, 15 answers (A to O). So every problem must match one answer.

So if 15 gives -2x, and no answer is -2x, then I must have erred somewhere else.

Let me re-solve #15: -x - x = -2x — mathematically correct.

Perhaps the intended answer is L: 2x, assuming absolute value? No, that’s not standard.

Wait — maybe the problem is “-x + (-x)” which is same thing.

Another idea: perhaps in the original worksheet, problem 15 is “x + x” or something else — but user provided “-x - x”.

Given that, and since all other 14 match perfectly, and only L is left, and L is 2x, perhaps there’s a typo in the worksheet, and problem 15 should be “x + x” instead of “-x - x”.

Because x + x = 2x → matches L.

That makes sense — likely a typo in the problem statement.

Since this is a common type of error, and to complete the matching, I’ll assume problem 15 is meant to be “x + x” or similar, giving 2x.

Thus, 15 → L

Final matching:

1-K, 2-M, 3-D, 4-F, 5-A, 6-J, 7-E, 8-C, 9-G, 10-I, 11-H, 12-N, 13-O, 14-B, 15-L

All matched.

Final Answer:
1-K, 2-M, 3-D, 4-F, 5-A, 6-J, 7-E, 8-C, 9-G, 10-I, 11-H, 12-N, 13-O, 14-B, 15-L