Can you please check my work? You have helped other students I know. Thank you:)

Multiply
-7(2a2 -4) = -14a2 + 28

Multiply
0.5(a + b -5) = 0.5a + 0.5b - 2.5

Factor
bx - by + bz = b(x - y + z)

Combine like terms (simplify)
12x + 4 - 11y - 6x - 9 - y = 6x - 12y - 5

Evaluate the expression
3x2y when x = 3 and y = 5
Answer: 135

Write as a fraction and simplify
Z-4
Answer: 1/z-4

Write using negative exponents
1/64
Answer: -6-4

Multiply and simplify
3-small2 • 3small6 = 81

Divide and simplify
4-small2/4small4 = 16

Divide and simplify
Y/y-5 = 1

Simplify
(2small3) -small2 =32

Simplify
(x-small1 ysmall1) small5 = ysmall5/xsmall5

Write in scientific notation
0.000005 = 5x10 -small6

Write in standard notation
31 x 10small7 =310,000,000

Perform the indicated operations (give your answer in scientific notation)
(5x10small2) x (5.6x10small4) = 2.8x10small6

Solve
X - 2.1 = -7.5
Answer: x = -5.4

Solve
2.3 = -y/2
Answer: y = -4.6

Solve
2 - x = 11 (x - 1)
Answer: x = 13/12

Please check my answers.

Did you see lidia's response?

http://www.jiskha.com/display.cgi?id=1320785885

Yes! Great! I wasn't sure if she was a tutor or not thank you.

Many of our questions are answered very well by other students.

I'm not really a math teacher, so I defer to answers that appear to be reasonable.

Evaluate the expression 3x2y when x = 3 and y = 5.

Sure, I can help you check your answers. Let's go through each problem one by one:

1. Multiply: -7(2a^2 - 4)
To multiply, you need to distribute -7 to each term inside the parentheses:
-7 * 2a^2 = -14a^2
-7 * -4 = 28
So the result is -14a^2 + 28.

Your answer: -14a^2 + 28
Correct!

2. Multiply: 0.5(a + b - 5)
Again, you need to distribute 0.5 to each term inside the parentheses:
0.5 * a = 0.5a
0.5 * b = 0.5b
0.5 * -5 = -2.5
So the result is 0.5a + 0.5b - 2.5.

Your answer: 0.5a + 0.5b - 2.5
Correct!

3. Factor: bx - by + bz
In this case, you can factor out the common factor b from each term:
b(x - y + z)
So the factored form is b(x - y + z).

Your answer: b(x - y + z)
Correct!

4. Combine like terms: 12x + 4 - 11y - 6x - 9 - y
To combine like terms, gather the terms with the same variables:
(12x - 6x) + (-11y - y) + (4 - 9)
Simplifying it further:
6x - 12y - 5
So the simplified form is 6x - 12y - 5.

Your answer: 6x - 12y - 5
Correct!

5. Evaluate the expression: 3x^2y when x = 3 and y = 5
Simply substitute the given values into the expression:
3(3)^2(5) = 3(9)(5) = 135
So the result is 135.

Your answer: 135
Correct!

Please let me know if you need further assistance with the remaining problems.