Question

If a line crosses the y-axis at (0, 1) and has a slope of 4/5, what is the equation of the line?

Answer 1

Slope intercept form is y = mx + b. m is the slope, and b is the y intercept. We know both of these! Just plug in the values.
y = 4/5x + 1.

Answer 2

Oh, it's in standard form. Get the x to the other side by subtracting.
y - 4/5x = 1.
Multiply everything by 5 to get rid of the fraction.
5y - 4x = 5.

Answer 3

thanks can you help me on a couple more problems ??

Answer 4

Yep.

Answer 5

If a line crosses the y-axis at (0, -4) and has a slope of -2, what is the equation of the line?

Answer 6

Is the answer supposed to be in standard form?

Answer 7

y = -2x -4 is the answer in slope intercept. To get standard form, add x to the other side.
y + 2x = -4.

Answer 8

thanks, one more ?

Answer 9

Now we do the opposite and turn it into slope intercept by isolating the y.
4x + 5y = -9.
Subtract the 4x from the left side.
5y = -9 -4x or 5y = -4x - 9, same thing.
Now divide everything by 5 to get y by itself.
y = -4/5x - 9/5.
We know that y = mx + b where m is the slope and b is the y intercept.
The slope is -4/5 and the y intercept is -9/5.