SamHenry

A negative is just a minus sign. So if you want negative 12, do -12. :) That's all there is to it!

Just add the two numbers: 9 + 10 = 19

No prob :)

On web2.0calc, just use a slash, / to make fractions. Just make sure the numerator and denominator are in parentheses.

Here's an example: (2x-4)/(x^2 - 3)

That's exactly how to do it - Area of a rectangle is width times height, so do 2.12 * .79.

2.12 * .79 = 1.6748 m^2

(Don't for get to include units meters squared)

To do sin-1 on web2.0calc, it is not sin-1: It is asin()

So do asin(value) to get what you want :)

2(2p + 3) + 4(p - 4)

You have to use the distributive property to simplify this expression. Multiply the outside number by both of the numbers in the parentheses, and then add the results together.

For 2(2p + 3), do 2 * 2p + 2 * 3

For 4(p - 4), do 4 * p + 4 * -4

So in all:

2 * 2p + 2 * 3 + 4 * p + 4 * -4

4p + 6 + 4p - 16

8p - 10

7 and 7/8 as a decimal: You can do one of two things: Convert the fraction to improper and solve, or just solve as it is.

The improper fraction is 63/8. Now do 63 divided by 8, which gives you 7.875 as the decimal.

The second way is to do 7 + 7 divided by 8. 7 + .875 = 7.875

3(x - 2)

When a number is by the parentheses, it is another way of saying multiply. So you can look at it like this:

3 * (x - 2)

Now use the distributive property to simplify this expression

3x - 6

Solving systems of equations requires you to solve one equation for a variable. Then plug that equation into the second equation, and solve. Here's an example:

Equation 1: y = 2x + 5
Equation 2: -5x = y + 2

Since you already know from the first equation that y = 2x + 5, put 2x + 5 into the second equation, and solve.

-5x = (2x + 5) + 2
-5x = 2x + 7
-7x = 7
x = -1

Now plug in x to one equation to solve for y:

y = 2(-1) + 5
y = 3