Algebra point slope help?
I have posted SO many questions about this part of math, and no matter what, I CAN'T understand it! Please help.
Find the point that lies on the line described by the equation below.
y - 5 = 6(x - 7)
A. (7, -5)
B. (5, 7)
C. (42, 5)
D. (7, 5)
Please and thanks :]
- 1 decade agoFavorite Answer
Point slope formula is just y - (y1) = m (x - (x1)) where y1 and x1 are coordinates of a point on the line and m is the slope.
y - y1 = m(x - x1)
y - 5 = 6(x - 7)
From just that, you can see that y1 = 5 and x1 = 7, which gives the coordinates (7, 5).
But if you're stuck on that, you can move the 5 over and get rid of the parentheses. Then you'll get the formula in common form, y = 6x - 37.
If you substitute in the x-values given in the answers, you can find the y-values that will correspond. Starting with A, if x = 7, y = 5, so A isn't the answer, but D is right.
y = 6(7) - 37
y = 42 - 37
y = 5
The coordinates are (7, 5)
- 1 decade ago
The answer is D.
To find the answer, you should know the point slope formula.
y - k = m(x - h)
In this version of the equation, (h, k) is the point. so you just find h and k in the original problem, and take them and plug it in. In this case, h = 7 and k = 5, so the answer is (7, 5).
Just make sure that both h and k are subtracted, because if they are added that means they are really negative numbers. for example:
y - 5 = 6(x + 7)
If this was the case, it doesn't look the like original point slope formula, because it has an addition sign in it. So, make it a subtraction sign:
y - 5 = 6(x - ( -7) )
Which means h = 5, and k = -7, so the point would be (5, -7).
I hope this helps!
- δοτζοLv 71 decade ago
Point-slope form is as follows
y - h = m(x - g), where m is the slope of the line and the point (g,h) is on the line.
So for yours g = 7 and h = 5 so the point is (7,5)
The problem with the occurs when something like this comes up.
y + 3 = x - 2
For this you have to create the form by remembering that minus a negative is plus and that when there is nothing there it is understood to be 1. so by rewriting you get.
y - (-3) = 1(x-2)
So your slope is 1 and the point would be (2, -3)
I just made that up.