Algebra & Formulae

Using letters for unknowns, forming and solving simple equations, and substituting into formulae

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1
If n + 4 = 9, what is the value of n? n = ___
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2
What does 3n mean in algebra? A) n + 3 B) n - 3 C) 3 × n D) n ÷ 3
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3
Is this statement true or false? If x = 4, then 2x + 1 = 9. A) True B) False
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4
Solve: x - 7 = 3 x = ___
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5
Solve: 3n = 18 n = ___
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6
Solve: 2x + 3 = 11 A) x = 3 B) x = 4 C) x = 5 D) x = 7
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7
Put these steps in the correct order to solve 4n - 2 = 10. Put these in order: n = 3, 4n = 12, 4n - 2 = 10, Divide both sides by 4, Add 2 to both sides
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8
A taxi charges £3 plus £2 per mile. The formula is C = 2m + 3. How much does a 7-mile journey cost? £___
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9
I think of a number, double it and add 5. The answer is 19. What was my number? A) 6 B) 7 C) 8 D) 12
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10
Is this statement true or false? The perimeter of a rectangle with length n and width 3 is 2n + 6. A) True B) False
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Answer key

Algebra & Formulae · for parents and teachers

1
5
n + 4 = 9, so n = 9 - 4 = 5.
2
3 × n
3n means 3 multiplied by n. The multiplication sign is left out in algebra.
3
True
2x + 1 = 2 × 4 + 1 = 8 + 1 = 9. The statement is true.
4
10
x - 7 = 3, so x = 3 + 7 = 10.
5
6
3n = 18, so n = 18 ÷ 3 = 6.
6
x = 4
2x + 3 = 11. Subtract 3: 2x = 8. Divide by 2: x = 4.
7
4n - 2 = 10, Add 2 to both sides, 4n = 12, Divide both sides by 4, n = 3
Start with 4n - 2 = 10. Add 2: 4n = 12. Divide by 4: n = 3.
8
17
C = 2 × 7 + 3 = 14 + 3 = £17.
9
7
2n + 5 = 19. Subtract 5: 2n = 14. Divide by 2: n = 7.
10
True
Perimeter = 2(n + 3) = 2n + 6. The statement is true.