Index laws in algebra Worked Solutions — GCSE Maths

Fully worked, step-by-step solutions to GCSE Index laws in algebra questions. See exactly how to solve problems on multiplication law, adding indices, division law, subtracting indices.

multiplication lawadding indicesdivision lawsubtracting indicespower lawmultiplying indices
GCSE Foundation70 questionsStep-by-step solutions
Question 1
1 markeasy
Simplify x2×x3x^2 \times x^3.

Worked solution

  1. Recall the multiplication law

    am×an=am+na^m \times a^n = a^{m+n}

    When multiplying powers of the same base, keep the base and add the indices.

  2. Add the indices

    x2+3x^{2+3}

    The base x stays the same and the indices 2 and 3 are added.

  3. State the answer

    x5x^{5}

    Two plus three is five, so the answer is x to the power 5.

Answer
x5x^{5}
Question 2
1 markeasy
Simplify y4×y5y^4 \times y^5.

Worked solution

  1. Recall the multiplication law

    am×an=am+na^m \times a^n = a^{m+n}

    Multiplying powers of the same base means adding the indices.

  2. Add the indices

    y4+5y^{4+5}

    Keep the base y and add 4 and 5.

  3. State the answer

    y9y^{9}

    Four plus five is nine, so the answer is y to the power 9.

Answer
y9y^{9}
Question 3
1 markeasy
Simplify x7÷x3x^7 \div x^3.

Worked solution

  1. Recall the division law

    am÷an=amna^m \div a^n = a^{m-n}

    When dividing powers of the same base, subtract the indices.

  2. Subtract the indices

    x73x^{7-3}

    Keep the base x and subtract 3 from 7.

  3. State the answer

    x4x^{4}

    Seven minus three is four, so the answer is x to the power 4.

Answer
x4x^{4}
Question 4
1 markeasy
Simplify y8y2\frac{y^8}{y^2}.

Worked solution

  1. Recall the division law

    am÷an=amna^m \div a^n = a^{m-n}

    A fraction of powers with the same base means subtract the indices.

  2. Subtract the indices

    y82y^{8-2}

    Keep the base y and subtract 2 from 8.

  3. State the answer

    y6y^{6}

    Eight minus two is six, so the answer is y to the power 6.

Answer
y6y^{6}
Question 5
1 markeasy
Simplify (x3)2(x^3)^2.

Worked solution

  1. Recall the power-of-a-power law

    (am)n=amn(a^m)^n = a^{mn}

    A power raised to another power means multiply the indices.

  2. Multiply the indices

    x3×2x^{3 \times 2}

    Keep the base x and multiply 3 by 2.

  3. State the answer

    x6x^{6}

    Three times two is six, so the answer is x to the power 6.

Answer
x6x^{6}

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