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Write an equation in slope-intercept form

for a line that goes through the points
(-4, 6) and (3,9).
S CAR

1 Answer

4 votes

Answer:

y = 3/7x + 54/7

Explanation:

(not sure what S CAR is)

(-4, 6) & (3, 9)

First you want to find the slope of the line that passes through these points. To find the slope of the line, we use the slope formula: (y₂ - y₁) / (x₂ - x₁)

Plug in these values:

(9 - 6) / (3 - (-4))

Simplify the parentheses.

= (3) / (3 + 4)

= (3) / (7)

Simplify the fraction.

= 3/7

This is your slope. Plug this value into the standard slope-intercept equation of y = mx + b.

y = 3/7x + b

To find b, we want to plug in a value that we know is on this line: in this case, I will use the second point (3, 9). Plug in the x and y values into the x and y of the standard equation.

9 = 3/7(3) + b

To find b, multiply the slope and the input of x(3)

9 = 9/7 + b

Now, subtract 9/7 from both sides to isolate b.

9 - 9/7 = b

[convert 9 to have a denominator of 7]

63/7 - 9/7 = b

54/7 = b

Plug this into your standard equation.

y = 3/7x + 54/7

This is your equation.

Check this by plugging in the other point you have not checked yet (-4, 6).

y = 3/7x + 54/7

6 = 3/7(-4) + 54/7

6 = -12/7 + 54/7

6 = 42/7

6 = 6

Your equation is correct.

Hope this helps!

User David Mckee
by
8.1k points

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