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, substitute x=4 into the expression:
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.