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Are the lines associated with the given functions parrallel ,perpendicular, or neither
f(x)=4x+9, g(x)=1/4x+3
I already solved it but not that sure 
My answer is they are not parallel nor perpendicular 

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Katherine P. | Experienced Math and Test Prep TutorExperienced Math and Test Prep Tutor
5.0 5.0 (572 lesson ratings) (572)
You are correct, the lines fit neither condition.
The equations are already in slope-intercept form, so you can see the slope of the first line is 4 and the slope of the second line is 1/4.
1.) To be parallel, the slopes would need to be equal.
2.) To be perpendicular, the slopes would need to be the negative reciprocal.
You can use the above rules for any similar question about two lines. Just find the slopes then evaluate using the two rules.
Grigori S. | Certified Physics and Math Teacher G.S.Certified Physics and Math Teacher G.S.
Slope of two lines have to be equal for thenlines to be parallel. In your case the slopes are different:
for the first line the slope is m1 = 4 for the second one m2=1/4 - not parallel. For the lines to be perpendicular these two slopes have to satisfy the following condition
                                            m1xm2 = -1
In your case m1xm2 = 4x(1/4) = 1 - not perpendicular.
Answer: neither