Question

Find the value of x for which the points (x,-1)(2, 1) and (4, 5)
are collinear.​

Answer 1

Answer:

x = 1

Step-by-step explanation:

If the 3 points are collinear, it means they share the same gradient.

Find the gradient of (2, 1) and (4, 5):

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

gradient = ( 5 - 1) / (4 - 2)

gradient = 4 / 2

gradient = 2

Find the gradient of (x, -1) and (2, 1):

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

gradient = ( 1 + 1) / (2 - x)

gradient = 2 / ( 2 - x)

Solve x:

2 / (2 - x) = 2

2(2 - x) = 2

4 - 2x = 2

2x = 2

x = 1

Answer: x = 1

Answer 2

Answer:

You have to see the above pic. for the given question's answer