SOLUTION: The graph of a linear function F passes through the point (-2,10 ) and has a slope of -2. What is the zero of F? *

Algebra ->  Linear-equations -> SOLUTION: The graph of a linear function F passes through the point (-2,10 ) and has a slope of -2. What is the zero of F? *      Log On


   

Question 1179547: The graph of a linear function F passes through the point (-2,10 ) and has a slope of -2. What is the zero of F? *
Found 3 solutions by MathLover1, josgarithmetic, greenestamps:
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

if the graph of a linear function F%28x%29 passes through the point (-2,10 ) and has a slope of -2, use point slope formula to find equation

F%28x%29=y
y-y%5B1%5D=m%28x-x%5B1%5D%29
y-10=-2%28x-%28-2%29%29
y-10=-2%28x%2B2%29
y-10=-2x-4
y=-2x-4%2B10
y=-2x%2B6

the zero of F is:

0=-2x%2B6
2x=6
x=6%2F2
x=3
the zero of F is at (3,0)







Answer by josgarithmetic(39617) About Me  (Show Source):
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


You should certainly know how to use the formal mathematical formulas to answer the question, as shown (in slightly different ways) by the other tutors.

But your understanding of the overall problem will be greater if you think in common sense terms about why those formulas work.

A slope of -2 means you go down 2 units for every unit you move to the right when "walking" along the graph.

You are given a point (-2,10) on the graph, and you are asked to find the x value when the y value is 0.

To get from y=10 to y=0 you need to go down 10 units; since you go down 2 units for every 1 unit you move to the right, you need to move 10/2=5 units to the right to get to where y is 0.

5 units to the right from your starting point at x=-2 puts you at x=-2+5=3.

ANSWER: x=3 when y is 0