al gebra2 problem ? plz help!!!?

Question

(-1,-4) perpendicular to y=2x+5
write an equation of the line

Answer 1

Perpendicular lines have opposite reciprocal slope. The given line has a slope of 2, so the perpendicular line would have a slope of -1/2. Since you are given a point, you can use use the point-slope form, y - k = m(x - h), where m is the slope and (h,k) is a point on the line. You can convert that to slope-intercept form using arithmetic if you like.

Answer 2

The product of the slopes of perpendicular lines is -1. So, you know the slope of the perp. line. You also know that the line goes through (-1,-4).

s*2 = -1
s=-1/2

So, for any (x,y) on the line the slope is constant:
(y-(-4))/(x-(-1)) = s = -1/2
y+4 = -1/2*(x+1) = -1/2x-1/2
y = -1/2x-9/2


Now check your answer:
at x=-1 -> y=-4 ok
slopes -1/2*2 = -1 ok

Answer 3

y=mx+b (p0int sl0pe f0rmula)
theref0re y=2x+5 is a p0int sl0pe f0rmula. it means that whatever is the c0efficient 0f x is y0ur sl0pe. in this case.. y0ur sl0pe is 2.

when it says perpendicular, it means that the sl0pe 0f the tw0 line is negative inverse of the sl0pe 0f hte 0ther line..

it means that the sl0pe 0f the line given (-1,-4) is -1/2. then y0u can n0w s0lve it using the p0int sl0pe f0rmula which is:
y-ysub1=m(x-xsub1)

ysub1= -4
xsub1=-1

y+4=-1/2(x+1)
2y+8=-x-1
x+2y+9=0 (this is the final answer)

h0pe y0u understand it!:)