A-Level Maths Edexcel 9MA0

Auth manager not initialized

#1 Use laws of indices

You can use the laws of indices to simplify powers of the same base.

"Index" (plural: "indices") and "exponent" mean the same thing as "power".

The laws of indices:

  • ax×ay=ax+ya^x×a^y=a^{x+y}
  • ax÷ay=axya^x÷a^y=a^{x-y}
  • (ax)y=axy(a^x)^y=a^{xy}
  • (ab)x=axbx(ab)^x=a^xb^x

Also remember:

  • a0=1a^0=1

Example 1

Simplify x2×x3x^2 \times x^3

x2+3=x5x^{2+3} = x^5

Example 2

Simplify x7÷x4x^7 \div x^4

x74=x3x^{7-4} = x^3

Example 3

Simplify (x3)4(x^3)^4

x3×4=x12x^{3 \times 4} = x^{12}

Example 4

Simplify (2x)4(2x)^4

24×x4=16x42^4 \times x^4 = 16x^4

Example 5

Simplify x5×x2x3\dfrac{x^5 \times x^2}{x^3}

x5+2x3=x7x3=x73=x4\dfrac{x^{5+2}}{x^3} = \dfrac{x^7}{x^3} = x^{7-3} = x^4

Example 6

Simplify (x2)3×(x4)2(x^2)^3 \times (x^4)^2

x2×3×x4×2=x6×x8=x6+8=x14x^{2 \times 3} \times x^{4 \times 2} = x^6 \times x^8 = x^{6+8} = x^{14}