Question

find an equation for the line with the given properties
Question: Perpendicular to the line x − 2y = −5; containing the point (0, 4)

Answer 1

so put that equation in this form: y=mx+b

Answer 2

so we can find the slope of the perpendicular line after we do that

Answer 3

Do you need help putting in that form?

Answer 4

1. Convert equation to y=mx+b, to find slope
2. Our second slope is the negative reciprocal of the given line's slope
3. Substitute the new slope, and the values of x and y into y=mx+b to solve for b (the y-int)

Answer 5

I am not understanding

Answer 6

Do you know how to write the equation given in this form: y=mx+b?

Answer 7

no i do not

Answer 8

You are just trying to solve for y:
\[x-2y=-5\]
\[\text{ add } 2y \text{ on both sides }\]
\[x-2y+2y=-5+2y\]
\[x=-5+2y\]
Now add 5 on both sides
\[x+5=2y\]
Now divide both sides by 2
\[\frac{x+5}{2}=y =>y=\frac{x}{2}+\frac{5}{2} =>\frac{1}{2}x+\frac{5}{2}\]
so what is the slope here?

Answer 9

1/5=5 & 2/2=1, is that right

Answer 10

y=mx+b where is m is slope
so what is in front of x up there?
1/2 right?
so what is the slope of a perpendicular line to this one?
in other words what satisfies this equation
1/2 * ? = -1

Answer 11

-1/2

Answer 12

close -2 would be the slope of the perpendicular line

Answer 13

so we have all lines are in this form y=mx+b
=> this line has this form: y=-2x+b

Answer 14

now we know a point on the line (0,4)

Answer 15

where x=0 and y=4
so we have enough info to find b

replace x with 0 and y with 4

4=-2(0)+b
how do you solve this for b?

Answer 16

wouldnt you multiply each side by -4

Answer 17

4=0+b since -2(0)=0

4=b since 0+b=b

Answer 18

so the equation us y=-2x+4