6t^3 x 6t^3

A.12t^3
B.12t^6
C.36t^6
D.36t^9

-3(4x+5)

A.7x+15
B.7x-15
C.-12x-15
D.-12x+15

5k^2(-6k-2k+6)

A.-30k^3+3k^2+30k
B.30k^4-10k^3+11k^2
C.-k^4+3k^3+11k^2
D.30k^4-10k^3+30k^2

(-4x).9x^2

A.-36^3
B.-36x^2
C.5x^3
D.5x^2

My answers are cbaa

-3(4x+5)

= -12x - 15 which is C

5k^2(-6k-2k+6)
= -30k^3 - 10k^3 + 30k^2
which is none of them.
I suspect a typo, why would you have two like terms in the bracket ?

the others are correct

To solve these questions, you will need to apply the rules of multiplication and simplification for algebraic expressions.

Question 1: 6t^3 x 6t^3

To multiply two terms with the same base, you can simply multiply their coefficients and add their exponents. In this case, the coefficient is 6, and the exponent is 3 for both terms.

6t^3 x 6t^3 = 6 * 6 * t^3 * t^3 = 36 * t^(3+3) = 36t^6

Therefore, the correct answer is B. 12t^6.

Question 2: -3(4x+5)

When we distribute a negative sign to a group of terms inside parentheses, we need to flip the sign of each term. Start by multiplying -3 by both terms inside the parentheses.

-3(4x+5) = -3 * 4x + (-3) * 5 = -12x + (-15) = -12x - 15

Therefore, the correct answer is B. 7x - 15.

Question 3: 5k^2(-6k-2k+6)

Again, start by distributing 5k^2 to all the terms inside the parentheses.

5k^2(-6k-2k+6) = 5k^2 * (-6k) + 5k^2 * (-2k) + 5k^2 * 6 = -30k^3 - 10k^3 + 30k^2

Combine like terms:

-30k^3 - 10k^3 + 30k^2 = -40k^3 + 30k^2

Therefore, the correct answer is C. -k^4 + 3k^3 + 11k^2.

Question 4: (-4x) · 9x^2

To multiply two terms, you simply multiply their coefficients and add their exponents. In this case, the coefficient is -4 and the exponent is 1 for x.

(-4x) · 9x^2 = -4 · 9 · x · x^2 = -36x^(1+2) = -36x^3

Therefore, the correct answer is A. -36x^3.