Work out the value of 2a^2 + b^3 when a = 5 and b = –3

It is best to approach this question in parts, then combine the parts to find your solution. This question may be split into parts, as follows: Firstly, if a = 5, then a² = 5² = 5 x 5 = 25. So a² = 25 Secondly, if b = -3, then b³ = (-3)³ = (-3) x (-3) x (-3) = 9 x (-3) = -27. So b³ = -27 Finally we can combine the above parts: 2a² + b³ = 2(25) + (-27) = 2 x 25 - 27 = 50 - 27 = 23 So the value of 2a² + b³ is 23.