please help..this stuff be confusing 10 pts. given?

Question

alright i have this math problem..well i have several.

the ask to fine the equation for the slope and y-intercept that is given.

can someone please help me with this one problem and explain what to do?

the problem states "Write an equation for the line with the slope 2 that passes through the point (4, 12).

I get that 2 is the slope and the x part of the equation but I dont understand what to do with (4,12) and how to get the y-intercept. please help and explain.

Thanks so much. 10 points to whoever gets me unstuck.

Answer 1

There are several ways to do this, but since you mention y-intercept, we'll go that way.

You should know the formula y = mx + b. In that formula "m" is the slope. You are given a point (x,y). Plug in all three of those numbers, and solve for "b". Here you'd have
12 = 2*4 + b
12 = 8 + b
4 = b
"b" is the y-intercept, which here is 4.

Go back and plug "m" and "b" into the formula.
Your answer is y = 2x + 4.

Answer 2

Well, when writing coordinates, it goes (x,y). The first number is therefore the x-intercept and the second is the y. So 4 is the x-intercept and 12 is the y-intercept. What you have so far is this:

12 = 2 * 4 + b

Now solve it like an equation. Simplify and get this: 12 = 8 + b

Subtract 8 from both sides and you come up with 4 = b.

So plug in the numbers and you get the answer. If the equation of the line is: y=mx+b, then plug in the m and the b, and there you go! =D (Didn't want to give you the exact answer, but I explained most of it.)

Answer 3

Use the following equation when you're doing these questions: y=mx+b, where m=slope and b=y intercept.

Since they already give you the slope, plug it into the formula: y=2x+b.

Now substitute whatever point they give you into the equation. In this case, it's (4,12). Think back to coordinates. The first number equals x and the second number equals y. So: 12=2(4)+b

All you have to do now is move things around to isolate b.
12=2(4)+b
12=8+b
12-8=8-8+b
4=b

Just plug the answer into your equation: y=2x+4, and write a concluding statement: Therefore, the equation of this line is y=2x+4

Answer 4

First, set up your equation like this: 12 = 2(4) + b. B is the y-intercept, 12 is the y from your ordered pair, and 4 is the x from your ordered pair.
Solve for b:
12 = 8 + b
b = 4
So the y-intercept is four!

Answer 5

ohh easy...
okay

so:
y=2x+___
so what you have to do is get graph paper and put a dot at 4,12. go up and over one and keep going. draw a line through the pionts. the reason why you do that is because 2/1. and that is how you plot. so the y intercept would be 10. the equation would be:

y=2x+10
hope i helped.
haha im only in 9th grade : ]

Answer 6

you dont actually have to put it in slope intercept form unless the question asks for it
you can use the point slope formula
y-y1 = m ( x - x1)
so in this case y-12=2(x-4)
but if you do need it in slope intercept form
y = mx + b
fill in the y, x, and m, and solve for b
m is the slope, and be is the y-intercept
hope this helps

Answer 7

do the following
y-12 (the y-coordinate) =2(the slope)*(x-4 (the x-value))
so
y-12=2(x-4) -> y-12=2x-8 --add 12 to both sides-->y=2x+4

Answer 8

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Answer 9

I hated Algebra but maybe this site can help you

http://www.purplemath.com/modules/strtlneq.htm