Give an equation of the line through the point (2, 5) with slope –3/4.

Question

mathstudent55 · Answer

The equation of a line in point-slope form is 

y = mx + b

where m = slope, and b = y-intercept.

yanasidlinskiy · Answer

Ok. Wow. Read it wrong. Sorry about that.

mathstudent55 · Answer

You are given the slope, so rewrite the equation I gave you above, and substitute the value of the slope for m.
Do that and show what you get.

mathstudent55 · Answer

Then substitute the x- and y-coordinates of the point you are given for x and y, and calculate b.
Finally, rewrite the equation using the given slope and the y-intercept you calculated.

anonymous · Answer

OK so
y=(-3/4)x+5
?

mathstudent55 · Answer

You start by just substituting m with the actual slope you were given

$y = -\dfrac{3}{4}x + b$

Now to find b, we use the x- and y-coordinates of the given point and we solve for b.
We use the equation with slope -3/4, and we plug in 2 for x and 5 for y.

$5 = -\dfrac{3}{4} \times 2 + b$

$5 = -\dfrac{3}{2} + b$

$5  +\dfrac{3}{2} = b$

$\dfrac{10}{2}  +\dfrac{3}{2} = b$

$\dfrac{13}{2} = b$

Now that we know the value of b, we plug it back into our equation with the known value of the slope.

$y = -\dfrac{3}{4}x +\dfrac{13}{2} $

anonymous · Answer

Ohhh thanks!

mathstudent55 · Answer

You're welcome.