Question

Evaluate this expression : 5x^3 - 7/4x^2. x=2

Answer 1

5(2)^3-7/ 4(2)^2 =  5(8) - 7 / 4(4) = 40-7/ 16 = 33/16

1. Substitute 2 in to the places where x are.
2.solve the square root first then multiply whats outside the square root with the numbers. (2)^3 = 8 and (2)^2 = 4, now multply 5 x 8 = 40 and multiply 4 x 4= 16
3. subtract 7 from 40 to get 33.
4. Check if it can be further simplified, this cant so the answer is 33/16