Need help to simply this problem: If p(x)=8x+9, find p(-3)

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- Apr 11th 2007, 03:30 AMeliciaevaluate function
Need help to simply this problem: If p(x)=8x+9, find p(-3)

- Apr 11th 2007, 04:00 AMDivideBy0
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