1. Rearrange the equation to make $x$ the subject.
x24−x3=6
x(24−3)=6
x=24−36
2. Rationalise the denominator by multiplying the numerator and denominator by the conjugate.
x=(24−3)(24+3)6(24+3)
3. Expand and simplify the numerator and denominator.
x=24−3144+18
x=2112+9×2
x=2112+32
4. Simplify the fraction and compare with the given form to find $a$ and $b$.
x=213(4+2)
x=74+2
Comparing with 7a+b, we have a=4 and b=2.