Question

A line passes through (2,-1) and (4,5). Which answer is the equation of the line?

Answer 1

Answer:

C.

Step-by-step explanation:

Slope = m = (y2 - y1)/(x2 - x1) = (5-(-1))/(4 - 2) = 6/2 = 3

Slope - point form:

y - y1 = m(x -x1)

y - 5 = 3(x - 4)

y - 5 = 3x - 12

- 3x + y = - 12 + 5

- 3x + y = - 7

Answer 2

Answer:

$- 3x + y = - 7$

Option C is the correct option.

Step-by-step explanation:

A line passes through ( 2 , -1 ) and ( 4 , 5 )

The equation of line:

$\frac{y - y1}{x - x1} = \frac{y2 - y1}{x2 - x1}$

Plug the values

$\frac{ y - ( - 1)}{x - 2} = \frac{5 - ( - 1)}{4 - 2}$

When there is a ( - ) in front of an expression in parentheses, change the sign of each term in the expression

$\frac{y + 1}{x - 2} = \frac{5 + 1}{4 - 2}$

Add the numbers

$\frac{y + 1}{x - 2} = \frac{6}{4 - 2}$

Subtract the numbers

$\frac{y + 1}{x - 2} = \frac{6}{2}$

Reduce the numbers with 2

$\frac{y + 1}{x - 2} = 3$

Apply cross product property

$3x - 6 = y + 1$

Move variable to L.H.S and change its sign

Similarly, Move constant to R.H.S and change its sign

$3x - y = 1 + 6$

Add the numbers

$3x - y = 7$

$- 3x + y = - 7$

Hope this helps...

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