The line whose slope is 4 and intersects the line 2x - 4y = 8 at x = 6 has the equation: a. y = 4x + 6 b. y = 4x + 1 c. y = 4x - 23

2x - 4y = 8   →   -4y = -2x + 8   →   y = - 2

We know the slope (m) = 4, need to find y-intercept (b)

y = 4x + b

- 2 = 4x + b

- 2 = 4(6) + b

3 - 2  = 24 + b

1 = 24 + b

-23 = b

Equation: y = 4x - 23

C

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional