# math

posted by
**Taylour** on
.

I need help with this question.

Write the equation of the line which contains the point)0, -3) and whose slope is 4.

A general line equation can be written as

y = mx + c, where m is the slope and c a constant.

so we can write this as y = 4x + c

Substituting the point (0, -3) in the equation, we have

-3 = c

So the equation is

y = 4x - 3

or 4x - y - 3 = 0

The explanation is long but i try to go step by step with it so you can understand it.

first use the formula of line which is :

y=mx+b

you have already your slope which is : 4 which in the formual for line would be your letter m. so substitute that in.

now they give you a set of point. which is (0,-3). NOw you know that 0 is your x point and -3 is your y point.

therefore looking at the equation of the line you substitute these two numbers like so.

y = mx +b

so , you have already the following:

y = 0

x = -3

m = 4

so the equation looks like this now after you substitute.

0=4(-3)+b now you find b so you do the following:

0= -12+b

0+12 = b

12=b

so now you write the equation of the line again:

y=mx+b

so your equation you just substitue the m and b and that would be your answer and it should look like this

y=4x+12

sorry g you are incorrect because they already gave the point and you need to find for b . in your case you put c. so your finding for c.

Yes, Jasmine20, we had to find the constant and I did exactly that. You misread the point (0, -3). The x is 0 and y is -3.

Thank you so much for explaining this

jasmine. It now makes sense.

TAMMY SORRY I DIDN'T REALIZE I DID USE THE Y WRONG AND X JUST REVERSE THEM BUT THE STEPS ARE THE SAME. AND THEN YOU SHOULD GET

Y=4X-3

SORRY FOR THAT LITTLE MISTAKE. i WAS TYPING QUICK AND I DIDN'T CATCH THAT.

SO THEN

(0,-3)

-3=4(0)+B

-3=B

Y=4X-3