Need to get the answer to this problem by using elimination: =x-3y=61 and 2x+y=-7

Solution:

1. 2x –  =y=61
2. 2x +   y= =7

If you subtract the second equation from the first, you can eliminate x and you are left with -4y = 68.

So y = 3D -17, and plugging this into the first equation we can figure out

y:  2x = (-51)=61,

so x = 5

What is 9/10 of 80?

Solution:

The expression “9/10 of 80” can be written as

This is equal to 72.

What is the name of a 6-sided polygon?

Solution:

A six-sided polygon is known as a Hexagon:

I had 48 marbles in my jar. I lost 1/8 and gave 1/6 to my best friend. How many marbles were left in my jar?

Solution:

1. Start with 48
2. Lost 6  (1/8 of 48 =s 6)
3. Gave 8 to a friend   (1/6 of 48 is 8)
4. 48 – 6 – 8
5. = 48 – 14
6. = 34

Solve equation. Round to nearest hundredth if neccessary. 11xsquared+3=5(4xsquared-3)

Solution:

1. The equation you gave us:
2. Can be re-written =s: or or
3. The Solution is:
4. This can also be written in an approximate decimal form: +1.41 and -1.41

I need help with solving systems by graphing. this is one of the problems y=5x-2 y=x+6

Solution:

First write down the two equations and then pick several values of x and use those values to calculate the corresponding values of y. You can use the  x,y pairs to then plot each line. You will see that the two lines intersect at 2,8 =i.e. x=2 and y=8).

Find the domain of the function. f(x)= 2x^2+5x+3/2x^2-5x-3

Solution:

First, let’s plot  f(x) =

Here’s what the graph looks like:

Now, the definition of “domain of a function” as follows: The domain of a given function is the set of “input” values for which the function is defined.” For instance, the domain of cosine would be all real numbers, while the domain of the square root would be only numbers greater than or equal to 0 (ignoring complex numbers in both bases).

As you can see from the above graph, the function is valid for all “real” values of x, except for 0. The set of “real numbers”, as you may know, can be thought of as points on an infinitely long number line. The shorthand way of saying “all real numbers except for x” is as follows:

How do you make a T chart for the problem y=2x^2+4x-5

Solution:

First, you have to have a clear idea what y = 2x^2+4x-5 means. This is an equation that tells you that, for any value of x, you can find y by dividing by multiplying x by x, and then multiplying that by two, adding 2 times x and finally subtracting 5. Does that sound familiar?

Now, what is the table you have to make? You will list several values of x (which you will be using as x-coordinates in your graph), and for each one use the equation to find what y is. We’ll show the work:

For x = 1, y = 2*1*1    +    4*1   –   5    =    1

For x = 2, y = 2*2*2    +    4*2   –   5    =  11

For x = 3, y = 2*3*3    +    4*3   –   5    =  25

For x = 4, y = 2*4*4    +    4*4   –   5    =  43

For x = 5, y = 2*5*5    +    4*5   –   5    =  65

Do you see what we did there? We just replaced x in the equation by each value of x, and did the multiplication and addition.

Now your table will look like this:

x |  y

–+—–

1 | 1

2 | 11

3 | 25

4 | 43

5 | 65

We’ve only shown the x,y values for 1 through 5, out there are an infinite number of x values that you could plug in, including negative numbers and fractions. You can use the resulting T chart to help you create a graph, which will look like this:

The total area of a cylinder is 40. If height = 8, find the radius. (The formula for total area used in class is: Total area = 2πrh + 2πr²)

Solution:

The total area is  40π=2πrh+2πr^2
=2πr*8 + 2πr²
=16πr + 2πr²
=16r + 2r²

If we rearrange the terms and divide the terms by 2 (in order to simplify the equation), we get:

r² + 8r – 20 = 0

(r+10)  (r-2) = 0

r = 2  or  -10

Therefore, r = 2 (assuming that -10 is not an option!).

I need to know how to do problems like this, I want to know how to solve, and simplify them, and also finding slopes. Like these kinds of problems(Write the equation, 3x + 5y = 15, in the slope intercept form (y = mx + b))

Solution:

1. Start with an equation like 3x + 5y = 15
2. Move 3x to the other side, so 5y = 15 – 3x
3. Divide both sides by 5, so y = 3 – x
4. Another way of writing this is y = -.6x + 3, or y=mx = b, where m=-0.6 and b = 3
5. If m = -0.6, that means that the slope = -0.6