Need help to simply this problem: If p(x)=8x+9, find p(-3)
If you have p(-3), simply substitute it into the formula where x is:
Hence, p(x) = 8x + 9
so...... p(-3) = 8(-3) + 9 = -24 + 9 = -15
In general:
If you have p(something), substitute something into the formula where the variable which the formula is concerned with used to be:
e.g
f(x) = 2x^2 + x - 1
f(x+1) = 2(x+1)^2 + (x+1) - 1
f(x^2) = 2(x^2)^2 + (x^2) - 1
f(0) = 2(0)^2 + (0) - 1
f(4) = 2(4)^2 + (4) - 1
etcetc