SOLUTION: For the straight line defined by points (4,55) and (6,83) determine the slope (m) and the y-intercept (b). Do not round up.

Algebra ->  Linear-equations -> SOLUTION: For the straight line defined by points (4,55) and (6,83) determine the slope (m) and the y-intercept (b). Do not round up.      Log On


   



Question 1209474: For the straight line defined by points (4,55) and (6,83) determine the slope (m) and the y-intercept (b). Do not round up.
Found 2 solutions by greenestamps, ikleyn:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The two given points are (4,55) and (6,83). We need to find the slope m and the y-intercept b.

(1) Finding the slope

Informally....

Going from (4,55) to (6,83) we move 2 units (6-4) to the right (positive direction) and 28 units (83-55) up (positive direction). So the slope is 28/2 = 14.

Formally....

slope = rise/run = change in y divided by change in x

%28y2-y1%29%2F%28x2-x1%29=%2883-55%29%2F%286-4%29=28%2F2=14

ANSWER #1: the slope is m=14

(2) Finding the y-intercept

Informally....

The y-intercept is the y value when x is 0. From the first point (4,55) we need to move 4 units to the left to get to where x is 0. In moving 2 units to the right from (4,55) to (6,83) we moved up 28 units; moving 4 units to the left is twice as far as moving 2 units to the right, and in the opposite direction. So we need to move 2*28=56 units down (in the y direction) from (4,55) to reach the y-axis. 56 units down from y=55 puts us at y=-1. So the y-intercept is -1.

Formally....

The equation is y=mx+b, and we have determined that the slope m is 14. Using that equation with the x and y coordinates of the first point and the slope of 14....

55=14%284%29%2Bb
55=56%2Bb
55-56=b
b=-1

ANSWER #2: the y-intercept is -1


Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.

As you go two units to the right from the point (4,55), you go 83-55 = 28 units up along the straight line.


It means that the slope is 28/2 = 14.     the ANSWER for the slope


To find y-intercept, you should go 4 units to the left from the point (4,55).


Hence, you should move 14*4 = 56 units down along the straight line.


Thus, y-intercept is at y= 55-56 = -1.    the ANSWER for the y-intercept

Solved.

This solution is to make you smile.