# Math Help - Work Check

1. ## Work Check

Hi again. I have a few problems that I would like looked over please. The double parentheses are the very large parentheses. My answers are annotated in bold numbers. Red numbers are exponents.

Problem 1: (( 3 a2 b c-1))-2
....................9 a-1 b-1 c

(3)-2 (a2)-2 (b)-2 (c-1)-2
(9)-2 (a-1)-2 (b-1)-2 (c)-2

-9 a4 b2 c2
-81 a2 b2 c2

9 c4
a6b4

_______

Problem 2: x-2a +6 = x3(a-3)

-2a + 6 = 3a – 9

-2a – 3a = 9 – 6

-1a = 3
- 1... -1

a = -3

________

Problem 3: (The asterisk is the multiplication sign): y5a – 6 * y2-a = ya+8

5a-6 * 2-a = a+8

5a – 12-a = a+8

5a – a -12= a+8

4a – 12 = a+8

4a + a = 8+12

5a = 20
5......5

a = 4

________

Problem 4:

3 c5 d3
6 c3 d5

c2 d2
...2

________

Problem 5:

-24 a b3
..8 a b2

-3b

________

Problem 6:

48 x2 y3
16 x y z2

3xy2
..z2

Thank you.

2. Originally Posted by slykksta
Hi again. I have a few problems that I would like looked over please. The double parentheses are the very large parentheses. My answers are annotated in bold numbers. Red numbers are exponents.

Problem 1: (( 3 a2 b c-1))-2
....................9 a-1 b-1 c

(3)-2 (a2)-2 (b)-2 (c-1)-2
(9)-2 (a-1)-2 (b-1)-2 (c)-2

-9 a4 b2 c2
-81 a2 b2 c2

9 c4
a6b4

_______
Your last two lines are disturbing. You got the final answer correct, but that second to the last line is just garbage. Did you simply forget to put the negative signs on the exponents?

Originally Posted by slykksta
Problem 2: x-2a +6 = x3(a-3)

-2a + 6 = 3a – 9

-2a – 3a = 9 – 6

-1a = 3
- 1... -1

a = -3

________
This is good.
Originally Posted by slykksta
Problem 3: (The asterisk is the multiplication sign): y5a – 6 * y2-a = ya+8

5a-6 * 2-a = a+8

________
$y^{5a - 6}y^{2 - a} \neq y^{(5a - 6)(2 - a)}$
The addition of exponents rule, remember?
$a^na^m = a^{n + m}$

So
$y^{5a - 6}y^{2 - a} = y^{(5a - 6) + (2 - a)}$

Originally Posted by slykksta
Problem 4:

3 c5 d3
6 c3 d5

c2 d2
...2

________
Great!

Originally Posted by slykksta
Problem 5:

-24 a b3
..8 a b2

-3b

________
Great!

Originally Posted by slykksta
Problem 6:

48 x2 y3
16 x y z2

3xy2
..z2

Great!

-Dan

3. ## Too many notes :-(

I had worked this out several times on paper and forgot to scratch this one out when I attempted to copy the right process for the first problem. Thanks for catching it.