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Help me find the x int.

Help me find the x int.-example-1
User Pepys
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2 Answers

13 votes
13 votes

Answer:

x-intercept is at (-14,0)

Explanation:

First find the equation of the straight line in slope-intercept form using the given points

Equation of a straight line in slope-intercept form

y = mx + b (1)

where m = slope and b is the y-intercept

Slope can be calculated using any two of the three given points, computing their y difference values and dividing by the corresponding difference in x values

If (x₁, y₁) and (x₂, y₂) are two points on the line, slope


m = (y_2-y_1)/(x_2-x_1)

Choosing the points (-74, 18) and (-54, 12)


m = (18-12)/(-74-(-54) )= (6)/(-74+54) = (-6)/(20) = -0.3

Plugging value of m in equation (1)

y = -0.300x + b (2)

To find the value of b, the y-intercept, we can select any of the points, plug in x and y values and solve for b

Let's choose the first point which we have not used

We have x = -94, y = 24

Plugging these values into equation (2)

24 = -0.3(-94) + b

24 = 28.2 + b

b = 14-28.2 = -4.2

Therefore b = -4.2 and the equation of the line is

y = -0.3x - 4.2

The x intercept can be found by setting y = 0 in the above equation and solving for x

Setting y = 0 we get

0 = -0.3x -4.2

0.3x = -4.2

x = (-4.2)/0.3 = -14

Therefore x-intercept is at (-14,0)

Help me find the x int.-example-1
User Hector Scout
by
2.6k points
7 votes
7 votes
(-14,0) this is i think the correct answer i’m doing this not on khan academy just by myself
User Wajax
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3.0k points