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

Which answer is the equation of the line.
A: -3x+5y=-13
B: -3x+y=-7
C: -3x+5y=13
D: -3x+y=17

1 Answer

2 votes

Answer:

Explanation:

The equation of a straight line can be represented in the slope-intercept form, y = mx + c

Where c = intercept

Slope, m =change in value of y on the vertical axis / change in value of x on the horizontal axis

change in the value of y = y2 - y1

Change in value of x = x2 -x1

y2 = final value of y

y 1 = initial value of y

x2 = final value of x

x1 = initial value of x

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

y2 = 5

y1 = - 1

x2 = 4

x1 = 2

Slope,m = (5 - - 1)/(4 - 2) = 6/2 = 3

To determine the intercept, we would substitute x = 4, y = 5 and m= 3 into y = mx + c. It becomes

5 = 3 × 4 + c

c = 5 - 12 = - 7

The equation becomes

y = 3x - 7

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