Answer:
- x-intercept (9, 0)
- y-intercept (0, 17.5)
Explanation:
You can compute the slope from two of the points, then write the point-slope form of the equation of the line.
slope = (change in y)/(change in x)
= (15 -20)/(3 -1) = -5/2
Then the equation of the line, using the first point) is ...
y = m(x -h) +k . . . . . . for slope m through point (h, k)
y = -5/2(x -1) +20
The x-intercept is the value of x where y=0:
0 = -5/2(x -1) +20 . . .put 0 where y is in the equation, then solve for x
0 = (x -1) -8 . . . . . . . . multiply by -2/5 (the inverse of the x-coefficient)
9 = x . . . . . . . . . . . . . simplify, add 9
The x-intercept is (9, 0).
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The y-intercept is the value of y where x=0:
y = -5/2(0 -1) +20 . . . . . . put 0 where x is in the equation, then solve for y.
y = -2.5 +20 = 17.5
The y-intercept is (0, 17.5).
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