Question

A line whose slope is 4 and passes through the point (0, -9) lies on the line whose equation is:

A. 4x + y = -9
B. 4x - y = 9
C. y - 4x = 9

Answer 1

y = mx + b

m is the slope
b is the y-intercept

so replace 'm' with 4

and then to solve for 'b', plug in the point (0, -9)
That's in the form of (x, y)
so replace x with 0 and y with -9

and then solve for b

Answer 2

can I have the equation so its clear for me

Answer 3

Let's do it, step by step

The slope-intercept form for an equation is this
y = mx + b

they told you the slope is 4

replace 'm' with 4

what do you get so far when you replace 'm' with 4

Answer 4

\[y= 4x+b \]

Answer 5

Good

now they told you this line passes through the point (0, -9)

points are written in the form of (x, y)

so replace x with 0
and y with -9

what do you get then?

Answer 6

\[-9=40+b\]

Answer 7

that wat i about said

Answer 8

no, 4x means 4 * x

so 4 * 0

-9 = (4 * 0) + b

Answer 9

what is 4 * 0 = ?

and then can you solve for b?

Answer 10

ohh ok

Answer 11

0 right?

Answer 12

yes, 4 * 0 = 0

so we have

-9 = 0 + b

so what is b?

Answer 13

maybe y? i dont know

Answer 14

uhh no?

anything plus 0 is going to be that number

so b is -9

Answer 15

so we have

y = mx + b

where m is 4
and we just found that 'b' is -9

we have

y = 4x - 9

can you re-arrange this equation and see which of the answer choices it would match up to?

Answer 16

Hint: subtract y on both sides and then add 9 on both sides