Can someone correct these for me please...

Multiply. (x+2)(x-2)

My answer..x^2-4

Write in descending-exponent form, and give the degree

4x^5+x^8-7

My answer: In descending-exponent form would be: x^8+4x^5-7, The degree is 8

Multiply. 3xy^2(5xy-4x+6y)

My answer: 13x^2y^2+18xy^3

the first two are correct, the last is not You should have three terms. The first term will be 15x^ 2 y^3

To correct the last expression, you should distribute 3xy^2 to each term within the parentheses: 3xy^2 * 5xy - 3xy^2 * 4x + 3xy^2 * 6y.

1. Multiplying 3xy^2 by 5xy, we get 15x^2y^3.
2. Multiplying 3xy^2 by -4x, we get -12x^2y^2.
3. Multiplying 3xy^2 by 6y, we get 18xy^3.

Combining these terms, the correct answer is 15x^2y^3 - 12x^2y^2 + 18xy^3.