Question

If a= 2^x and b =2^x+1; show that: 8a^3 / b^3 = 2^x+1​

Answer 1

Explanation:

Given that:

a = 2ˣ

b = 2ˣ⁺¹ = 2ˣ * 2¹ = 2.2ˣ

Now,

{(8a³)/b²}

Substitute the value of x and y in expression then

= [{8(2ˣ)³}/(2.2ˣ)²]

= [(8*2³ˣ)/{2² * (2ˣ)²}]

= {(8*2³ˣ)/(4 * 2²ˣ)}

[since, (aᵐ)ⁿ = aᵐⁿ]

= {(2 * 2³ˣ)/2²ˣ}

= {(2 * 2²ˣ * 2ˣ)/2²ˣ}

[since (2a = a+a, that means 3x = 2x + x)]

= 2 * 2ˣ

= 2ˣ⁺¹

[since (aᵐ * aⁿ = aᵐ+ⁿ)]

Answer: Therefore, {(8a³)/b²} = 2ˣ⁺¹ .

Please let me know if you have any other.