1. 2000 – n = -2000

-n = -2000 – 2000

-n = -4000

n = 4000

2. 1.2 x 10^9 … scientific notation is basically dropping the zeros so that there’s only one number before the decimal. You then have to multiply your new decimal by the number ten to some power… notice that 1.2 x 10^9 = 1,200,000,000 … it’s used a lot in science.

3. This is basically scientific notation in reverse.

3.048 x 10^9 = 3,048,000,000

4. The 12,500 isn’t needed. So Jim needs $1500 for a downpayment and only needs $350 more. So say n is the amount he has already. Solve for n.

350 + n = 1500

n = 1500 – 350

n = 1150

Jim has $1,150 saved already for the downpayment.

5. Let n be the cost of fabric for a yard. So the cost of 3/4 of a yard (or (3/4) x n) is $3. Plug and chug.

(3/4) x n = 3

n = 3 / (3/4)

n = 3 x (4/3)

n = 4

A yard of fabric costs $4.

1. Find the value of n: 2,000 – n = -2,000

2000-n=-2000 so subtract 2000 -n=-2000(-2000) -n=-4000 so divide by -1 to make n positive -n/-1=-4000/-1=

n=4000

2. The population of china is about 1,200,000,000 people. Rename this number using scientific notation. 1,200,000,000= 1.2 x 10 to the 9th power. the 9 would be little and up by the 10.

3. The wavelength of x-rays in cm is 3.048 times 10 to the power of nine. Rename this using decimal notation.

3,048,000,000

4. Figure out ONLY this problem using the following property:

24=16+a —-> 24 -16= 16+a -16 —-> 8=a

A new car cost 12,500 By saving $350 more, Jim will have saved enough $ for the down payment he needs of $1500. How much does Jim already have saved?

1500=350+a—> 1500-350=350+a-350 —>$1150

5. If 3/4 yard of fabric cost $3.00, what does a full yard cost?

3/4 is $3 so a full yard would be $4

(see 1/4 yd =$1 2/4 yd=$2 3/4yd=$3 so 4/4 yd=$4)

I will give you some hints….

2000 – n = -2000

You can use this simple rule. You can freely move numbers or variables across the equal sign by changing the sign. For example, all of the below are the same.

2000 – n = -2000

2000 = -2000 + n

2000 + 2000 = n

Scientific notations are ones such as

1.0 * 10^2 which translates to 100 in decimal system. The digits before the * symbol indicates significant digits and is always greater than 1 and less than 10. The expression after the * symbol indicates how many zeros you will have.

With these rules, you should be able to figure out most, if not all of your problems.

1) 2000-n= -2000

Subtract 2000 to both sides to solve for n

2000-n = -2000

-2000 -2000

_____________

-n= -4000

now divide both sides by -1

-n/ -1 = -4000/-1

n= 4000

2) 1.2 x 10 to the 9th power (scientific notation is writing a number in base ten exponents. The decimal goes directly after the first number then you can count decimal places after that to the right to determine the exponent on 10)

3) 3,048,000,000 cm (This is the reverse of scientific notation. I moved the decimal 9 places to the right)

4) I have to be honest and say that I am not sure what you are asking for on this problem.

5) 3/4 x = 3.00

change the 3/4 to a decimal and rewrite equation

.75x=3.00

Now divide both sides by .75 to solve for x

.75x/.75 = 3.00/.75 (x represents the price of a full yard)

x=4.00 SO a whole yard is $4.00

****Check this answer by multiplying 4.00 times .75 (or 3/4) if your answer comes out 3.00 than you know you did it correctly.

Hope this helps!

1. 3x+9=27 what does x= ? x=6 First, subtract 9 from 9 and 27, to get 18, then divide 3 and 18 by three to get x=6. All you’re doing is isolating the variable. 2. -5y-4=76 what does y= ? -16 3. 10-1/4b=9 what is b= ? 4 4. 4c+7-6c=23 what does c= ? -8 This one, you combine 4c and -6c (add) to get .2c Then you do what I explained earlier. 5. 13d-53=9d+19 what does d= ? Subtract the 9d from the 13d to get 4d-53=19 and do the other steps I explained. Answer’s 18. 5/6e+18-1/6e=6 whats e? 25-3/9f=19+4/7f whats f? 3(y+4)-10=66-5y what is y? Distribute. 3y+12-10=66-5y so that’s 3y+2=66-5y answer’s -8 4(g-2)=2(g+8) what is g? Distribute again. 4g-8=2g+16 answer is 12

1. 2,000 – 4,000 = -2,000 so n= 4,000

2. 1.2 x 10^9

3. 3.048 x 10^9 = 3,048,000,000 (move the decimal over 9 places)

There are the first 3

ok well 1 is

2,000-4,000= -2,000 here is how(i made it like a numberline

2000_{2000}_0_{2000}_-2000

^<<<2000+2000>^ = 4000

4 is $4

1/4= $1 2/4=$2 3/4=$3 4/4(or 1) = $4

im only 12 yrs old so i dont kno 2 or 3 but i hope i helped!

btw i need help!!!!!http://answers.yahoo.com/question/index;_ylt=AhYyE4HS8_mx.wXSYNOwUxzsy6IX?qid=20070902190649AA6OQAE

1. Add N to both sides, then add 2000 to both sides.

2000 – n + n = -2000 + n; 2000+2000 = -2000 +2000 +n;n=4000

2. 1.2 x 10^9

Look it up on Wikipedia.

3. 3048000000 cm

Wikipedia

Eh… I’m bored now.

2) 1.2 x 10^9

http://www.nyu.edu/pages/mathmol/textbook/scinot.html < explanation on what scientific notation is

by the time you typed this, you could have figured at least half of them out.