Question

Help please!!
If a line passes through the point (-1,2) and has a slope m=a/b, for a>0 and b>0, then which of the following point must lie on the graph of this line?
A (-1+b, 2-a)
B (-1-a,2-b)
C (-1+b, 2+a)
(D was a wrong answer)

Answer 1

y = mx + c

y = (a/b)*x + c ... plug in m = a/b

2 = (a/b)*(-1) + c ... plug in (x,y) = (-1,2)

now we solve for c

2 = (a/b)*(-1) + c

2 = -a/b + c

c = 2 + (a/b)

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So the equation is

y = (a/b)x + 2 + (a/b)

from here, you test each point by plugging it into the equation above. If you get a true equation, then the point lies on the line.

Answer 2

the answer I got was c and it was right thanks!

Answer 3

np