Question

What is the equation of the line that passes through the point (2, 3) and is perpendicular to the line y = -x - 3?
Choose one answer.
a. y = -x - 1
b. y = -x + 5
c. y = x + 1
d. y = x + 5

Answer 1

first, do you know what the slope of the line y = -x - 3 is?

Answer 2

No is it -1 not really sure

Answer 3

yes its -1
next, you should know that the slopes of perpendicular lines multiply to give -1.
so if the line y = -x - 3 has slope -1, then what do you think will be the slope of a line perpendicular to this?

Answer 4

would it be 1

Answer 5

correct.
finally, the slope-intercept form of a line is written as:

y = mx + c

where m is the slope and c is the y-intercept.

now you know the slope is 1, so you can write the equation of the perpendicular line as:

y = x + c

all that remains is to put in the coordinate (2, 3) to calculate c. so put in x=2, y=3 into this equation to work out c and you have then solved the question.

Answer 6

I don't understand sorry I did 3=2+c is that right so far

Answer 7

that is correct, now find the value for c that satisfies this equation.

Answer 8

so I got c=1

Answer 9

perfect, so the answer to your question would be?

Answer 10

y=-x-1?

Answer 11

we ended up with:

y = x + c

and you found c=1, so answer is?

Answer 12

y=x+1?

Answer 13

thats it!

Answer 14

Thanks so much!

Answer 15

yw