PLEASE HELP WILL FAN AND MEDAL:

1. Brianna plotted the two points (20, 75) and (45, 150) on a graph.
1. Write the equation of the line in slope-intercept form.
2. What is the x-coordinate of the x-intercept of the line that contains these two points?

Question

PLEASE HELP WILL FAN AND MEDAL:

1. Brianna plotted the two points (20, 75) and (45, 150) on a graph. 
1. Write the equation of the line in slope-intercept form.
2. What is the x-coordinate of the x-intercept of the line that contains these two points?

anonymous · Answer

@johnweldon1993 do you think you could help me

johnweldon1993 · Answer

Well first we need to find the slope between these 2 points

$$\large m = \frac{y_2 - y_1}{x_2 - x_1}$$

anonymous · Answer

I got -3 as the slope

johnweldon1993 · Answer

Why -3?

$$\large \frac{150 - 75}{45 - 20}$$

anonymous · Answer

oh, I did it backwards

anonymous · Answer

it's positive 3

johnweldon1993 · Answer

Correct...now to put the points into slope intercept form...we just use the point slope formula

$$\large y - y_0 = m(x - x_0)$$

Pick which point you want to use...

anonymous · Answer

$$y - 75 = 3(x - 20)$$$$y - 75 = 3x - 60$$$$y = 3x + 15$$

johnweldon1993 · Answer

Correct!

And finally what is the x-coordinate of the intercept?

anonymous · Answer

is it 15

johnweldon1993 · Answer

Hmm are you sure? The X intercept occurs when y = 0

johnweldon1993 · Answer

15 would be the 'y' intercept

anonymous · Answer

$$0 = 3x + 15 $$$$-15 = 3x $$$$-5 = x $$
I did this equation... and I got -5 idk if this is correct or not

johnweldon1993 · Answer

That is exactly correct

anonymous · Answer

Great, thanks for your help :)