I'm doing ACT prep and I am not sure how to do this problem... f(x) = 3x2(2 hould be subscripted to make it squared) -5 for all real numbers x. What is f(-4)?
Well for one thing, we know f(x) is equal to y. It is the original function.
For f(x)=3x^2 -5
We want to find the y value when x=-4
So just plug in -4 for all the x's and get the y value.
f(-4)=3(-4)^2-5
f(-4)=3(16)-5
f(-4)=48-5
f(-4)=43
f(-4)=43=the y value at x=-4
So for the function f(x)=3x^2 -5
We know there will be a point at (-4,43)
Hope this helps! If you have any questions, just ask! :-)