What is the equation of a line that passes through the point (2, 4) and has a y-intercept at y = -10?

The equation of the line is y = 7x - 10

Step-by-step explanation:

* Lets revise the form of the equation

- The form of the equation of a line is y = mx + c , where m is the slope

  of the line and c is the y-intercept

- The y-intercept means the line intersect the y-axis at point (0 , c)

- The slope of the line which passes through points (x1 , y1) , (x2 , y2)

 is

* Lets solve the problem

∵ The y-intercept is y = -10

∴ The line intersects the y-axis at point (0 , -10)

∵ The line passes through the points (2 , 4) and (0 , -10)

- Lets find the slope of the line using the rule of the slope above

∵

∴ The slope of the line is 7

∵ c is the y-intercept

∵ The y-intercept is y = -10

∴ c = -10

∵ y = mx + c

∴ y = 7x + -10

∴ y = 7x - 10

* The equation of the line is y = 7x - 10

1.4

2.3

step-by-step explanation:

the formula for the constant of variation is

y= kx

divide each side by x

y/x =kx/x

y/x =k

we know a and y

1.   y/x = k

4/1 =4

check the other values to make sure they are the same

8/2 = 4   12/3 =4   and 16/4 =4  

the constant of variation is 4

2.   y/x = k

3/1 =3

check the other values to make sure they are the same

6/2 = 3   9/3 =3   and 12/4 =3  

the constant of variation is 3