# math help & correction

posted by
**jacky** on
.

Problem #1

Is this correct or wrong?

Find the slope of the line passing through the points(-1, -1)and(-1, 2). Write the equation of the line.

For this one I KEEP GETTING

Y= - (3)/(2)x-2.5

Problem #2

Find the y-intecept and slope of

7x+9y=72

My answer:

Slope is: - (9)/(8)

y-intercept: (0,8)

The equation of a straight line is given by

(y2-y1)/(X2-x1)

In your example

Y2=2, y1=-1

x2=-1, x1=-1

substitute and find the slope

In the second part the general equation of a straight line is given by

y=mx+c where m=slope and c=intercept.

you need to compare the equation given with the general equation, but to do that they need to be in the same form

i.e y=mx+c

but 7x+9y=72 is not in this form

To get you started subtract 7x from each side:

9y=72-7x

but this is still not in the correct form so you still need to rearrange it.