Slope-Intercept Form

Question

m=-6,(1,3)

m=2,(7,9)

(2,9) and (4,7)

(-4,-12) and (-12,-14)

How would you write this in slope-intercept form when given the slope and a point and when you are given 2 points?

I really don't understand my homework and I need help please?

Answer 1

Given only two points,

You find the slope using the two points using the formula m = (y2-y1)/(x2-x1);

then you use the formula B = y - mx to find the intercept using one the points

Problem #1:

Given: the line has slope m=-6 and it eats point (1,3)

B = y - mx = 3 - (-6)*1 = 3 - -6 = 3 + 6 = 9

y = -6x+9

Problem #2:

Given the slope of the line is m=2, and passes through (7,9)

B = y - mx = 9 - 2*7 = 9 - 14 = -5

y = 2x - 5

Problem #3:

(2,9) and (4,7) are on the line...

the slope is m = (9-7)/(2-4) = 2/-2 = -1

Using (2,9)

B = y - mx = 9 - 2*-1 = 9 - -2 = 9+2=11

y = -1x+11 = -x+11

Problem #4:

(-4,-12) and (-12,-14)

slope M = (-14 - -12) / (-12 - -4) = (-14+ 12)/(-12 + 4) = -2/-8 = 1/4

B = y - mx = -12 - (1/4)(-4) <--- using (-4,-12)

= -12 - (-1)

= -12 + 1

= -11

y = (1/4)x - 11