Math homework help ?

Question

with coordinates (-3,1) and (7,4) - hw do i write an equation with them? and how do i find the y intercept and x intercept.

and how do i write the inverse of y=0.25x+10

Answer 1

try using this to get the equation

Y-Y1=m(X-X1)

*1 is a subscript

*m is the slope

first, get the slope

m=Y2-Y1/X2-X1

m=4-1/7-(-3)

m=4-1/7+3

m=3/10

after getting the slope, substitute the values:

Y-Y1=m(X-X1)

Y-1=3/10(X-(-3))

Y-1=3/10(X+3)

Y-1=3/10X+9/10

then, simplify. isolate Y

Y=3/10X+9/10+1

simplify again

Y=3/10X+19/10

thats the equation if it's in the form y=mx+b

b/y-intercept is equal to 19/10

to get the x-int, make y=0

0=3/10X+19/10

3/10X= -19/10

3X= -19

X-int= -19/3

inverse function:

y=0.25x+10

first, exchange the roles of y and x

x=0.25y+10

then simplify y

x-10=.25y

then divide .25 on both sides

y=4x-40--> inverse

Answer 2

To write an equation with two points you first find the slope, m:

(y1-y2)/(x1-x2)        (4-1)/(7-(-3))         3/11=m

use y=mx+b

use one of the coordinates for x,y

      1=(3/11)(-3)+b

Solve for b  

b=1.88

      y=(3/11)x+ 1.88