SOLUTION: Having already submitted one question, there is another along the same line I find equally confusing: Given the function f(x)= -7x^2 -14x +9, is the point (-2, -5) on the graph

Algebra ->  Rational-functions -> SOLUTION: Having already submitted one question, there is another along the same line I find equally confusing: Given the function f(x)= -7x^2 -14x +9, is the point (-2, -5) on the graph       Log On


   

Question 48379This question is from textbook
: Having already submitted one question, there is another along the same line I find equally confusing:
Given the function f(x)= -7x^2 -14x +9, is the point (-2, -5) on the graph of f?
Does the y=mx+b formula apply here, I just don't know, any help will be greatly appreciated This question is from textbook

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Does the point (-2, -5) lie on the graph of f%28x%29+=+-7x%5E2-14x%2B9?
Write your function in the form:
y+=+-7x%5E2-14x%2B9 and substitute x = -2, and y = -5 and see if the two sides are equal.
-5+=+-7%28-2%29%5E2-14%28-2%29%2B9 Simplify.
-5+=+-7%284%29%2B28%2B9
-5+=+-28%2B28%2B9
-5+=+9 Not true!
The point (-2, -5) does not lie on the graph of f%28x%29+=+-7x%5E2-14x%2B9