I need alittle help on algebra homework =/?

Question

First day back to school and lots of homework! 70 problems in algebra. Theres a few that I don't understand =( so if you could help me out a bit and explain how you get the answers that would be GREAT! We have to put them on the board tomarrow and I don't want to look stupid =/ I really need to learn this! Thnks:)

a=12, b=0.5, c= -3, d=1/3

1.) a[b^2(b+a)]

2.) 9c+ab/c

Okay, next section..

Simplify each expression.

1.) 2(5x+4y)- 3(x+8y)

2.) -5(a-4b)+4b

3.) 2m+7n-6m-5n

Any the next....=/

Solve each equation and check your solution.

1.) -2/3 a=14

2.) 3w+14=7w+2

3.) 5y+4=2(y-4)

4.) n/4 + n/3=1/2

Last section finally.

Solve each equation or formula for the specified variable.

1. Ax+By=C, for x

2. A=p+prt, for p

You don't have to answer all of them.. i just need to know how to work them for tomarrow's problems. If you could just answer a couple that would be awesome. Thanks so much.

Answer 1

*** 1.) a[b^2(b+a)] ***

Just substitute the values for each variable (letter):

12 [ .5^2 (.5 + 12)]

Then do what's in parenthesis first and work your way out.

12 [ .5^2 (12.5) ]

Now exponents....

12 [ .25 (12.5)]

12 (3.125)

Answer = 37.5

*** 2.) 9c+ab/c ***

First substitute the values again.

9 (-3) + (12)(.5) / -3

Multiplication first, from left to right.

-27 + 6 / -3

Now division.

-27 + (-2)

Since we're adding a negative 2, we can get rid of the +.

-27 - 2

Answer = -29

*** 1.) 2(5x+4y)- 3(x+8y) ***

Distribute the 2 and the 3 on their respective sides....

10x + 8y  on one side, 3x + 24y on the other.  You're just multiplying that outside number by each part in parenthesis.

10x + 8y - 3x + 24y

Now combine like terms (meaning x's and y's together)

Answer:  7x + 32y

*** 2.) -5(a-4b)+4b ***

-5a + 20b + 4b   (note that -5 times -4b will give a positive 20b)

Answer:  -5a + 24b

*** 3.) 2m+7n-6m-5n ***

Act like the variables are just telling you which numbers go together.

2m - 6m  and 7n - 5n

Answer:  -4m + 2n

*** 1.) -2/3 a=14 ***

Looks like you may have copied this one wrong.  There's no variable in the problem.

*** 2.) 3w + 14 = 7w + 2 ***

Subtract 3w from both sides.

14 = 4w + 2

Now subtract two from both sides.

12 = 4w

Now divide each side by 4.

Answer:  3 = w

*** 3.) 5y + 4 = 2 (y - 4) ***

Distribute the 2 on the right side first.

5y + 4 = 2y - 8

Now subtract 2y from both sides.

3y + 4 = -8

Subtract 4 from each side.

3y = -12

Divide each side by 3.

y = -4

*** 4.) n/4 + n/3=1/2 ***

Get a common denominator.  Let's use 12.

3n/12 + 4n/12 = 6/12

Now add like terms.

12n/12 = 6/12

12(.5) = 6, so....

Answer:  n = .5

I'm out of time here.... but for the last two, you just have to do what you do when there are numbers involved.... get that special variable to one side all by itself by adding and subtracting the others from each side.  So your #1 answer should be x= something, and your #2 answer should be p= something.

Good luck!

Answer 2

a=12, b=0.5, c= -3, d=1/3

1.) a[b^2(b+a)]

first, put given numbers into the equation

then, solve following the order of operations PEMDAS (in the US) or BEDMAS (Canada)  -- in this case you would do the work in parentheses/brackets first, then exponents, then multiplication/division, and lastly addition/subtraction.

Simplify each expression.

1.) 2(5x+4y)- 3(x+8y)

[(2 * 5x) + (2 * 4y)] - [(3 * x) + (3 * 8y)]

solve in the round brackets, then square brackets, and then subtract. Put like terms together (e.g. 2y + y = 3y)

Solve each equation and check your solution.

1.) -2/3 a=14

solve the equation, and then check if your answer is correct by replacing a with your answer.

Answer 3

An easy way to remember the order of operations is to turn PEDMAS into a sentence. The one that I learned was: Please Excuse My Dear Aunt Sally.

Parentheses (solve within them first)

Exponents (next in order)

Multiplication

Division

Addition

Subtraction (do last)