Find the value of the function y=3x2 -21 when x = 4
To find the value of the function y = 3x^2 - 21 when x = 4, we substitute 4 for x in the equation:
y = 3(4)^2 - 21
y = 3(16) - 21
y = 48 - 21
y = 27
Therefore, when x = 4, the value of the function is y = 27.