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

Friday, July 23rd, 2010

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?

Friday, July 23rd, 2010

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?

Friday, July 23rd, 2010

Solution:

A six-sided polygon is known as a Hexagon: What is the dimension of amount of a substance?

Friday, July 23rd, 2010

Solution:

In the physical sciences, the amount of a sample is often given in terms of moles (i.e. Avogadro’s number, or 6.02214179 x 1023):   A particle is trapped in an infinite one-dimensional well of width 0.132nm. The electron is in the n=10 state. A) What is energy of the electron? B) What is the uncertainty in its momentum?

Friday, July 23rd, 2010

Solution: 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?

Friday, July 23rd, 2010

Solution:

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

A lawyer commutes daily from his suburban home to his midtown office. The average time for a one-way trip is 24 minutes, with a standard deviation of 3.8 minutes. Assume the distribution of trips times to be normally distributed. Find the probability that 2 of the next 3 trips will take at least half(1/2) hour.

Friday, July 23rd, 2010

Solution: So, the probability that one of the trips takes more than 30 minutes is 0.05705343.

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

Friday, July 23rd, 2010

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

Friday, July 23rd, 2010

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

Friday, July 23rd, 2010

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: 