can someone tell me what im doing wrong in this math problem?

Question

(-2,8);m=5

y-8=5(x-(-2)

y-8=5x+10

so then i subtracted 8 from both sides and the 8 take away 8 gets canceled out leaveing you with 10 take away 8 so y=5x+2!

now its this problem is giving me problems
i followed the same steps! see?!

(1,-1);m=2

(y-(-1)=2(x-1)

y+1=2x+2
as i did the first one i subracted 1 from both sides and 1 take away one gets canceled out leaveing me with y=2x+1! since its 2 different signs i subtract see, positive 2 takeaway negative 1 is positive 1! so how is it y=2x-3?!



the first one i did is to show you i did it correct and i followed the same percedures as the 1st one.

Answer 1

You had an error in each problem you did.

In the first problem, when you subtracted 8 from each side, you did not cancel out the -8 on the left side of the equation. You should have added 8 to each side to do that.

y - 8 = 5x + 10
y - 8 + 8 = 5x + 10 + 8
y = 5x + 18

On the second problem, when you distributed the 2(x - 1) you should have gotten 2x - 2, not 2x + 2.

y - -1 = 2(x - 1)
y + 1 = 2x - 2
y + 1 - 1 = 2x - 2 - 1
y = 2x - 3

Got it?

Answer 2

There is something fishy in the first one, too! If y-8=5x+10 then y=5x+18. To get rid of a -8 you have to add 8 and not subtract it.

The second one:
y-(-1)=2(x-1) that's correct. Now comes the problem:
y+1=(2x)-(2×1) or 2x+2(-1), which is 2x-2 and not 2x+2.
Then you correctly subtracted 1 from both sides, but you had a wrong equation to begin with; performing that operation on the right equation indeed gives y=2x-3

Answer 3

When you got to
y - 8 = 5x + 10

you should add 8 to both sides, not subtract, because
y - 8 + 8 = y
but
y - 8 - 8 = y - 16

So you get
y = 5x + 18


In the second one, when you removed the parentheses from
2(x - 1)
you should get 2x - 2,
not 2x + 2,

and so in your last step, subtracting 1, you get
2x - 2 - 1 on the right side, and that's
2x - 3

Answer 4

I think there are careless errors in both examples. In the first one, you should ADD 8 to both sides to get

y=5x+18

You need to add the 8 in order to 'undo' the subtract 8.

In the second example, when you removed the parentheses you should get -2, not +2.

y+1=2x-2, now subtract 1 to undo the add 1 and get
y=2x-3

You obviously understand the major concepts but are careless. Try to be a little more careful. Good luck

Answer 5

Others already pointed out the errors you made. In addition, you have unmatched parenthesis (number of left and right parenthesis should be equal)

+++++

But I don't like the way you're doing it. This is how I would write the 2 equations given the slope (m) and one point the line goes through:

y = 5 * (x+2) + 8 = 5*x + 18

y = 2 * (x-1) - 1 = 2*x - 3

Answer 6

The first one is wrong too. it should be y=5x+18
you should add 8 to both sides, not subtract.

With the second one, you multiplied wrong.
(y-(-1)=2(x-1)

y+1=2x+2 <-----you multiplied wrong.
it should be -2 not +2
y+1=2x-2 <------this is right (2 x -1) = -2
-1= -1
----------------
y =2x-3

Answer 7

(1, -1) is your (x, y) coordinates
m=2 is your slope
You are trying to solve for y right?

y=mx+b
-1= 2(1)+ b
-1= 2+b
-2 -2
-3=b
So your new equation is
y=2x-3

Answer 8

y=mx+b b is the y-intercept

in the fiorst problem... y=mx+b
8=5(-2) + b
solve for b= -2
so the equation of the line would be y=5x-2

the 2nd one:
y=mx+b
-1=2(1) + b
solve for b= -3
equation of the line would be y=2x-3

hope this helps/is the right topic

Answer 9

you dont add the x and the y you must substitute them.