What is the value of 54-4a^2+3b^3 when a=-2 and b=4

2015-12-14T20:17:50+00:00If you would like to know what is the value of 54 - 4 * a^2 + 3 * b^3 when a = -2 and b = 4, you can calculate this using the following steps:

54 - 4 * a^2 + 3 * b^3 = 54 - 4 * (-2)^2 + 3 * 4^3 = 54 - 4 * 4 + 3 * 64 = 54 - 16 + 192 = 230

If you would like to know what is the value of 54 - 4 * a^2 - 3 * b^3 when a = -2 and b = 4, you can calculate this using the following steps:

54 - 4 * a^2 - 3 * b^3 = 54 - 4 * (-2)^2 - 3 * 4^3 = 54 - 4 * 4 - 3 * 64 = 54 - 16 - 192 = -154

54 - 4 (-2)^2 + 3 (4)^3 = y
54 - 4 (4) + 3 (64) = y
54 - 16 + 192 = y 
38 + 192 = y
230 = y

How am i goonna know explain