SOLUTION: Write an equation for each line. (Directions) (Question that I have to write an equation for: through point (1.2,5.1), x- intercept of 3.7 I tried this but do not know if I am c

Algebra ->  Linear-equations -> SOLUTION: Write an equation for each line. (Directions) (Question that I have to write an equation for: through point (1.2,5.1), x- intercept of 3.7 I tried this but do not know if I am c      Log On


   

Question 654094: Write an equation for each line. (Directions)
(Question that I have to write an equation for: through point (1.2,5.1), x- intercept of 3.7
I tried this but do not know if I am correct or far from the right answer:
5.1/1.2=y/3.7
5.1X3.7=1.2y
18.87=1.2y
15.7=y
(For slope) 15.7-5.1=10.6
3.7-1.2=2.5
10.6/2.5=4.24 (slope)
Final answer: y-5.1=4.24(x-1.2)
I hope you understood what I wrote and are able to help me. Thank you.
Found 2 solutions by josmiceli, MathTherapy:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
through point (1.2,5.1), x- intercept of 3.7
This is two points:
( 1.2, 5.1 ), ( 3.7, 0 )
These are in the format:
( x1 , y1 ) and ( x2 , y2 )
---------------------
Use the point-slope formula which is:
( y - y2 ) / ( x - x2 ) = ( y1 - y2 ) / ( x1 - x2 )
+%28+y+-+0+%29+%2F+%28+x+-+3.7+%29+=+%28+5.1+-+0+%29+%2F+%28+1.2+-+3.7+%29+
+y+%2F+%28+x+-+3.7+%29+=+5.1+%2F+%28+-2.5+%29+
Multiply both sides by +-2.56%2A%28+x+-+3.7+%29+
+-2.5y+=+5.1%2A%28x+-+3.7%29+
+-2.5y+=+5.1x+-+18.87+
+y++=+%28+-5.1%2F2.5+%29%2Ax+%2B+18.87%2F2.5+ answer
--------------------------
check: does the line go through ( 1.2, 5.1 ) ?
+5.1++=+%28+-5.1%2F2.5+%29%2A1.2+%2B+18.87%2F2.5+
+5.1+=+%28+-6.12+%2B+18.87+%29+%2F+2.5+
+5.1+=+12.75+%2F+2.5+
+5.1+=+5.1+
OK
Does it go through ( 3.7,0 ) ?
+0++=+%28+-5.1%2F2.5+%29%2A3.7+%2B+18.87%2F2.5+
+0+=+%28+-18.87+%2B+18.87+%29+%2F+2.5+
+0+=+0+
OK

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Write an equation for each line. (Directions)
(Question that I have to write an equation for: through point (1.2,5.1), x- intercept of 3.7
I tried this but do not know if I am correct or far from the right answer:
5.1/1.2=y/3.7
5.1X3.7=1.2y
18.87=1.2y
15.7=y
(For slope) 15.7-5.1=10.6
3.7-1.2=2.5
10.6/2.5=4.24 (slope)
Final answer: y-5.1=4.24(x-1.2)
I hope you understood what I wrote and are able to help me. Thank you.

I don't know what you have done here, but nothing seems to make sense.

The first thing you need to do is to determine the slope, and since one point was given, we use the given info that the x-intercept is 3.7 to locate a second point at (3.7, 0)

We now have 2 points: (1.2, 5.1) and (3.7, 0) which we will use to determine m, or the slope of the equation.

Using the slope formula: %28y%5B2%5D+-+y%5B1%5D%29%2F%28x%5B2%5D+-+x%5B1%5D%29, with y%5B2%5D+=+0; y%5B1%5D+=+5.1; x%5B2%5D+=+3.7; x%5B1%5D+=+1.2, we get:

%280+-+5.1%29%2F%283.7+-+1.2%29 ----- %28-+5.1%29%2F2.5, or -+2.04

Using the point slope formula: y+-+y%5B1%5D+=+m%28x+-+x%5B1%5D%29, with m, or slope = - 2.04; y%5B2%5D+=+0, and x%5B2%5D+=+3.7, we get:

y+-+0+=+-+2.04%28x+-+3.7%29 ----- highlight_green%28y+=+-+2.04x+%2B+7.548%29

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