select the equation that is perpendicular to y=1/4x+11 and passes through point (3,5)

Question

texaschic101 · Answer

can you tell me the slope of the equation given ?

anonymous · Answer

sadly no, but and it has to be in slope intercept form

texaschic101 · Answer

in y = mx + b form, the m is the slope.
so in y = 1/4x + 11...what is the slope ?

anonymous · Answer

i was not given the slope. the exact question is stated in the top.

texaschic101 · Answer

you have to find the slope in order to do these types of problems.
y = 1/4x + 11.....the 1/4 is in the m position, and is therefore the slope. Now if you needed a parallel line, the slope would stay the same. But you need a perpendicular line, therefore, the slope is the negative reciprocal of the slope in the equation. All that means is " flip " the slope and change the sign. The negative reciprocal of 1/4 = -4/1 or just -4 (see how I flipped the slope and changed the sign)

Now we will use y = mx + b and solve for b
slope(m) = -4
(3,5)  x = 3 and y = 5
now we sub
y = mx + b
5 = -4(3) + b
5 = -12 + b
5 + 12 = b
17 = b

so your perpendicular equation is : y = -4x + 17

does that make sense to you ? Any questions ?

anonymous · Answer

oooooooooooh k thanks this really helped a lot

texaschic101 · Answer

glad to help :)