Simplify 3 (5 a²+2 c) -2 a(1-3 a)-6 c.

Correct Answer is : 21a2−2a21 a²-2 a21a2−2a

Correct Answer is : 21a2−2a21 a²-2 a21a2−2a

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BECE Mathematics 2021 Paper

Question : 40

Total: 40

Simplify

3 (5 a^2+2 c) -2 a(1-3 a)-6 c

Solution:

Concept:

Apply the distributive property to remove brackets, then combine like terms.

Explanation:

Expand each term using

a(b+c)=ab+ac

First,

3(5a^2+2c) = 3 \times 5a^2 + 3 \times 2c = 15a^2 + 6c

Next, expand

-2a(1-3a)

. Since

- \times - = +

, we get:

-2a(1-3a) = -2a \times 1 + (-2a)(-3a) = -2a + 6a^2.

Now substitute into the expression:

3(5a^2+2c)-2a(1-3a)-6c = 15a^2 + 6c - 2a + 6a^2 - 6c.

Group like terms:

= (15a^2+6a^2) - 2a + (6c-6c) = 21a^2 - 2a + 0.

The

c

terms cancel, leaving

21a^2 - 2a

Answer:

21a^2 - 2a

Therefore, the correct option is D.

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