Evaluate the algebraic expression {ACT}

If x = 4 and y = 5, find the difference of y³ - 3x and x³ - 3y.
A.)  5
B.)  25
C.)  64
D.)  34
E.)  27

y³ - 3x - (x³ - 3y) {subtracting}
= y³ - 3x - x³ + 3y {distributed negative sign through parentheses}
= (5)³ - 3(4) - (4)³ + 3(5) {substituted 4 in for x and 5 in for y}
= 125 - 12 - 64 + 15 {evaluated exponents and multiplied}
= 64 {added and subtracted from left to right}

C.)  64

- Algebra House