Math Question??

Question

Find the equation of a line that has a y intercept of -4/5 and passes through the point (-2,5)?

^^ answer + directions please! ^^

Answer 1

You have enough information to solve for the slope, which is the only thing you still need. Just plug in our point and intercept into the equation:

y = mx + b
==> plug in numbers
5 = m(-2) - 4/5
==> add 4/5 to both sides
29/5 = m(-2)
==> divide by -2 on both sides
-29/10 = m

Now, we have our slope and y-intercept, so we can plug it into the equation and we have:

y = (-29/10)x - 4/5 ... ANSWER

Answer 2

so if the y intercept is -4/5 then the point is (0,-4/5) as well as the point (-2,5)

use the formula m = (y2-y1)/(x2-x1)

and this gives u the gradient.

so m = (5+4/5) / (-2-0)

dont hav calculator so not sure what that equals.

then u use the equation of a straight line, y=mx+c
so using the point (-2,5) u get:
5=m(-2) +c (u need to work out m above n use it in the formula)
then solve for c and that is ur constant value.

so the equation is y=mx + c (and u use the m and the c u hav worked out in the equation)

Answer 3

In slope-intercept form the equation is

y = (slope)*x + intercept
y = mx + b

You have the intercept, -4/5, so plug in the coordinates of the other point and solve for the slope:

5 = m(-2) + -4/5
25/5 = m(-2) + -4/5
29/5 = m(-2)
-29/10 = m

y = (-29/10)x - 4/5

Answer 4

coz u know the intercept u know that y=mx-4/5
then substitute in the point (-2,5) into that and u get 5=-2m-4/5
which means that 2m = -4/5 + 5 which simplifies to m = 21/10
so the equation of the line is y=21/10x-4/5 and if you multiply all that by 10 the equation would be 5y=21x-4 and that makes it look a whole lot more nicer so i think the answer is 10y=21x-8

Answer 5

It is simply a system of equation
The equation of the line is y = ax + b
You have two points (-2,5) and (0, -4/5), because x=0 on the y-intercept

plug in the second point in the line equation and you get

-4/5 = b

Therfore y = ax - 4/5. Now plug in the values of the other point and you get 5 = -2a -4/5 or a = -29/10 = -2.9

so the line is y = -2.9x - 4/5 or y = -2.9x - 0.8

Answer 6

If the line has a y-intercept of -4/5, it passes through the point (0,-0.8). It also passes through (-2,5). The slope of the line is

m = (y2 - y1) / (x2 - x1)

It doesn't matter whether (0, -0.8) is point 1 or vice versa.

The equation of the line is

y = m x + b, where m is calculated above, and you were given b, the y-intercept.

Go for it.

Answer 7

well, you know one of your points is (0, -4/5) or (0, -.8)and an another is (-2,5), so the slope of the line is (y-y1)/(x-x1)
= (5- -.8)/(-2 - 0) = 5.8 / -2 = -2.9
so this is your slope m in the equation y = mx + b.
b is the y-intercept which they already gave you, so you know the equation has to be:
y = -2.9x - .8

Answer 8

To verify what everyone else has written:

I also got y = (-29/10)x - 4/5. (using the y=mx+b format)

this is because you know that b is -4/5 because that is given and to find the slope you use the formula [(y2-y1)/(x2-x1)] and you get -29/10 as your M.

Simply adding these numbers in the formula you get y = (-29/10)x - 4/5

Hope this helps.

Answer 9

Yea dude this question isnt too difficult you can do it. if you want to find the slope, just know if a point is a Y INTERCEPT the 'x' value HAS to be zero ... right? then no prob, you have two points now u have (0,-4/5) and (-2,5) *<-given*... haha this is gonna be my answer to your question if u need more tell me i cant answer it mannnn~! that ruins the necessary struggles you need.

Answer 10

Y=mX + C, find m (slope) from the given info, and you can have the equation.
You can find any text book on Coordinate Geometry to do this kind of math.