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