Question

The points (-6, r) and (10,4) lie on a line with slope 1/2

Find the missing coordinate r.
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Answer 1

-4

Explanation:

½ = (r - 4)/(-6 - 10)

½ = (r - 4)/(-16)

r - 4 = -8

r = -4

Answer 2

r = -4

Explanation:

The slope of a line is given by

m= (y2-y1)/(x2-x1)

1/2 = (4-r)/(10 - -6)

1/2 = (4-r) (10+6)

1/2 =( 4-r) /16

Multiply each side by 16

16*1/2 = 4-r

8 = 4-r

Subtract 4 from each side

8-4= 4-r-4

4 = -r

Multiply each side by -1

-4 = r