where does the line cross the x-axis when the points are (-3,1) and (1,9)..also what is the equation for this?

Answer 1

The line crosses the x-axis at x=3.5. The equation for it is y=2x+7

Answer 2

x = m¯¹ y + a
Where m is the slope and a is the point where the line crosses the x-axis[Thus, the point (a,0) is on the line]

There are 2 given points (-3,1) and (1,9)
Substitute them separately into the first equation and solve for a.

-3 = m¯¹ (1) + a
1 = m¯¹ (9) + a

Simplifying the equations (and multiplying the first equation by -9)
27 = -9m¯¹ - 9a
1 = 9m¯¹ + a

Add the equations:
28 = -8a
-8a = 28
a = -7/2

Thus the line crosses the x-axis at -7/2 or -3 1/2

^_^

Answer 3

to come across a graph perpendicular to the line given, you may desire to discover the slope and get the alternative of the reciprocal. In different words, a line perpendicular to y=mx could be y=(-a million/m)x, so the slope of the equation is eighteen/7. the strategies above tells us that the line crosses the x-axis at 2, so a element on the graph is (2,0). in accordance to the element-slope notation, the equation is y-0=(18/7)(x-2). The greater common notation, however, is of the form y=mx+b, so we could desire to do a sprint re-association: y=(18/7)(x-2)=(18/7)x-(18/7)2=(18/7)x-... Voilà ! we've gained the equation for the perpindicular line which has an x-intercept of two !

Answer 4

ok, the line has a formula y = ax + b
you have 2 points - so when you set x to 1, you get y to be -3, and also for the second point. this way you can find out what a and b are.
-3 = a + b
1 = 9a + b

a = 5/8
b = -29/8

now you have formula for the line:
y = (5/8)x - 29/8

it crosses x-axis when y = 0 (and y axis when x = 0)
so you just say:
0 = (5/8)x - 29/8 and solve this (find out what x is)

that would be the point where it crosses x-axis (x,y) - y is 0, x you calculated

Answer 5

(-3,1) and (1,9)

m = (9 - 1)/(1 - (-3))
m = 8/(1 + 3)
m = 8/4
m = 2

(-3,1), m = 2
1 = 2(-3) + b
1 = -6 + b
b = 7

y = 2x + 7

0 = 2x + 7
2x = -7
x = (-7/2)

ANS : (-7/2)

Answer 6

ok here goes

first u have to find the equation of the line. u do this by the 2 point formula.

(y2-y1)/(y1-y)= (x2-x1)/(x1-x)

therefore: (9-1)/(1-y)= (1+3)/(-3-x)

8/1-y= 4/ -3-x

(cross multiply)

8(-3-x) = 4(1-y)

-24-8x = ............... omg i give up but u should get it

Answer 7

why dont you plot the straight line on a graph paper.eventho there is a simple method of doing it...but by drawing it,youll understand more.