# Simple high-school math problems

1. Feb 8, 2007

### vegaaan

Simple high-school math problems!!

I really need some help!! I am pretty bad at math and am having an awful lot of trouble with my homework.

1.) How do I graph by stating the x and y intercepts? How do I figure out what those are?

ex. x + y = 7
3x - 2y = 6

2.) How do I graph using the slope intercept form (y = mx + b)?

ex. y= -2x + 3
y = x - 2

3.) And lastly, how do I solve this question

0.2(4n + 1) = 0.5(n-2)??
!!!!!!!!! I just realized I posted this in the wrong forum. Sorry

2. Feb 8, 2007

### z-component

2) Look up the form y=mx+b to find out what m and b are, and learn how to find and use them.

3) Have you used the distributive property before?

The distributive property says that:

$$a(b + c) = a*b + a*c$$

3. Feb 8, 2007

### theperthvan

1) x-intercept when y=0
y-intercept when x=0

2) They are already in the y=mx + b form
Say y=2x-3, then m=2 and b=-3
that is, the gradient is 2 and the y intercept is at y=3 (since x=0, mx=0)

4. Feb 9, 2007

### Gib Z

ok dude, it seems like your only doing y=mx+b graphs right now.

Since theres lines are always straight, we just get any 2 points and draw the line that connects them. any 2 are fine, but x and y ints are easiest to work out, because zeros easy to work with.

5. Feb 10, 2007

### Holocene

To find the x-intercept, let y = 0 and solve the equation for x.
To find the y-intercept, let x = 0 and solve the equation for y.

In x + y = 7, both the x and y intercepts are 7.

In 3x - 2y = 6, the x-intercept is 2, and the y-intercept is -3.

In the equation y = mx + b, m is the slope and b is the y-intercept.

With regard to y = -2x + 3, you already know that (0,3) is a solution, since 3 is the y-intercept. Simply substitute another value for either x or y, solve the equation, plot the point, and graph the line. This is no different than graphing any other linear equation.

The same is true for y = x - 2. FYI, the coefficient of x is the slope, so in this case the slope is equal to 1.

And lastly, how do I solve this question

You solve it like any other equation. Start by removing the parenthesis by using the distributive property. This property states a(b + c) = ab + ac. So, your equation then becomes:

0.8n + 0.2 = 0.5n - 1

From here you can use the subtraction principle to cancel the 0.5n:

0.3n + 0.2 = -1

Use that principle again to cancel the 0.2:

0.3n = -1.2

Now use the division principle to solve for n:

n = 4

6. Feb 10, 2007

### z-component

For the future, you should never post full solutions to homework problems.

7. Feb 10, 2007