SOLUTION: Please help me solve this problem---- Write an equation in slope-intercept form for the line that contains the points (2, 1) and (-2, 10). my answer y=-9/4x -12-- wrong answer

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Question 657379: Please help me solve this problem---- Write an equation in slope-intercept form for the line that contains the points (2, 1) and (-2, 10).
my answer y=-9/4x -12-- wrong answer on the exam
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
an equation in slope-intercept form:
y=mx%2Bb
for the line that contains the points (2, 1) and (-2, 10), will be:
y=mx%2Bb....plug in given values for x and y from the point (2, 1)
1=m%2A2%2Bb...........1
y=mx%2Bb....plug in given values for x and y from the point (-2, 10)
10=m%2A%28-2%29%2Bb...........2
--------------------------------solve the system
1=2m%2Bb...........1

10=-2m%2Bb...........2
-------------------------------add 1 and 2
1%2B10=2m%2B%28-2m%29%2Bb%2Bb
11=cross%282m%29%2Bcross%28%28-2m%29%29%2B2b
11=2b......solve for b
11%2F2=b
highlight%285.5=b%29
now we can find m
1=2m%2Bb...........1
1-b=2m
1-5.5=2m
-4.5=2m
-4.5%2F2=m
highlight%28-2.25=m%29
so, our equation is:
y=-2.25x%2B5.5