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Simplification & Surds · Topic 3 of 8

⚡ Powers & Exponents

2 exam question types, fully solved

A power like 2⁵ just means “2 multiplied by itself 5 times”. Because of that, multiplying and dividing powers becomes simple arithmetic on the little numbers up top (the exponents).

The laws of indices

• aᵐ × aⁿ = aᵐ⁺ⁿ  (same base, multiply → add the powers)

• aᵐ ÷ aⁿ = aᵐ⁻ⁿ  (divide → subtract the powers)

• (aᵐ)ⁿ = aᵐⁿ  (power of a power → multiply the powers)

• a⁰ = 1  and  a⁻ⁿ =

The master move for equations: rewrite every number over the same base. Once the bases match, the powers must be equal. Example: 9ˣ⁺¹ = 27ˣ⁻¹ → (3²)ˣ⁺¹ = (3³)ˣ⁻¹ → 2(x+1) = 3(x−1) → x = 5.

For a sum of powers you cannot merge exponents — instead factor out the smallest power.

⚡Laws of IndicesPick a base & two powers
base a
power m
power n
aᵐ × aⁿ = aᵐ⁺ⁿ 2⁵ × 2³ = 2⁸ = 256
aᵐ ÷ aⁿ = aᵐ⁻ⁿ 2⁵ ÷ 2³ = 2² = 4
(aᵐ)ⁿ = aᵐⁿ (2⁵)³ = 2¹⁵ = 32768

2⁵ × 2³ = 2 to the power (add the powers: 5 + 3).

📝Practice Questions

Q1Simplify: 2⁵ × 2³ ÷ 2⁶

Q2If 3ˣ = 81, then x is:

Q3The value of (2⁰ + 3⁰ + 4⁰) is:

📚

Real exam questions — Powers & Exponents

2 question types · 6 solved examples from real SSC papers

Bring everything to one base and the laws of indices do the rest — add, subtract, or factor the exponents.

How to solve this type
Use the basic laws: aᵐ × aⁿ = aᵐ⁺ⁿ (multiply → add the powers), aᵐ ÷ aⁿ = aᵐ⁻ⁿ (divide → subtract the powers), (aᵐ)ⁿ = aᵐⁿ (power of a power → multiply the powers), a⁰ = 1, and a⁻ⁿ = 1/aⁿ. To compare two sides or solve an equation, first rewrite every number over the SAME base (or the same power); once the bases match, the exponents must be equal. If you are only asked to simplify, just add and subtract the exponents of the common base.

Simplify x9×x5×x−4×x0×x−6x^9 \times x^5 \times x^{-4} \times x^0 \times x^{-6}:

Ax6x^6Bx4x^4Cx−4x^{-4}Dx−6x^{-6}

If 9<sup>x+1</sup>=27<sup>x−1</sup>9<sup>x+1</sup> = 27<sup>x-1</sup>, find xx:

A6B7C4D5

If 2x=32^x = 3, find 2<sup>3x+1</sup>2<sup>3x+1</sup>:

A81B54C27D108