Please help......cannot find the slope?

Question

I need to find the slope and y-intercept of:

7x + 9y = 72

I cannot get this one correct....any help would be great...thank you.

Answer 1

Bring the equation to the form, (y = mx + c), where m = slope and c = y-intercept.

7x + 9y = 72
9y = -7x + 72
divide the equation by 9,
y = -7/9 x + 8

slope = -7/9
y-intercept = 8

Answer 2

Before you draw ANY conclusions about what the slope or y-intercept is from this equation, you have to ask yourself these questions:
1. Is this equation in fact a straight line?
The answer here is "yes" because it is an equation where the variables are no higher that x^1 or y^1. If it contained an x^2 or y^2 term, it's not a straight line.

2. Is my equation in Standard form?
No, it is not. Re-write your equation to conform to the
standard form y=mx+b
Your equation thus becomes y=-7/9x+8
I got there as follows:
7x + 9y =72
9y = -7x + 72
y = -7/9x + 8
Note that the key to "Standard" form is getting +1y all
by itself on the left side of the equation. Forget that and you're toast.
Once in Standard form, the slope m is the coefficient of the x term , including its sign. For your equation the slope is -7/9. The minus sign tells me the line is leaning to the left.
The y-intercept is the constant term, in this case +8.
This tells me the line crosses the y-axis 8 units above the origin, at the point (0,8).

That's all there is to it. Good luck!

Answer 3

you need to change it into slope-intercept form (not kidding, that's the actual name) which is y = mx + b

now if you don't know how to do that, you first need to understand what each one means:

y is of course the y-axis on your graph, or the second number in any point.

m is the slope.

x is the x-axis, and the first number in any point.

b is the y-intercept.

so back to the beginning, you need to change 7x + 9y = 72 into y = mx + b form.

to do that, you have to isolate the variable (y) first subtract 7x from both sides:

7x + 9y = 72
___ _______
-7x ..........-7x
__________
9y = -7x + 72

so your new equation is 9y = -7x + 72. now y is still not isolated, so you have to get rid of the coefficient (9) so divide 9 on each side:

9y = -7x +72
__ _______
/9.........../9
___________
y = -7/9x + 8

that is in y = mx +b form. so -7/9x is your slope (-7/9 took the place of "m") and 8 is your y-intercept (8 took the place of "b")

and those are the basic steps.

Answer 4

7x + 9y = 72

Transpose 7x

7x + 9y - 7x = - 7x + 72

9y = - 7x + 72

Divide both sides of the equation by 9

9y / 9 = - 7x / 9 + 71 / 9

y = - 7/9x + 8

- - - - - -

The slope is - 7/9

y intercept is 8

- - - - - - - -s-

Answer 5

9y=-7x+72
y=-7/9x+72/7
slope=-7/9
y-intercept =72/7