High School

Simplify: [tex]\left(5x^2 - 6x + 1\right)(4x + 9)[/tex]

A. [tex]20x^3 + 69x^2 + 58x + 9[/tex]

B. [tex]20x^3 + 21x^2 - 58x + 9[/tex]

C. [tex]20x^3 + 21x^2 - 50x + 9[/tex]

D. [tex]20x^3 + 69x^2 - 50x + 9[/tex]

Answer :

To simplify the expression [tex]\((5x^2 - 6x + 1)(4x + 9)\)[/tex], we need to distribute each term in the first polynomial by each term in the second polynomial.

Here's a step-by-step breakdown:

1. Multiply each term in [tex]\((5x^2 - 6x + 1)\)[/tex] by [tex]\(4x\)[/tex]:
- [tex]\(5x^2 \times 4x = 20x^3\)[/tex]
- [tex]\(-6x \times 4x = -24x^2\)[/tex]
- [tex]\(1 \times 4x = 4x\)[/tex]

2. Multiply each term in [tex]\((5x^2 - 6x + 1)\)[/tex] by [tex]\(9\)[/tex]:
- [tex]\(5x^2 \times 9 = 45x^2\)[/tex]
- [tex]\(-6x \times 9 = -54x\)[/tex]
- [tex]\(1 \times 9 = 9\)[/tex]

3. Combine like terms:
- The [tex]\(x^3\)[/tex] term: [tex]\(20x^3\)[/tex]
- The [tex]\(x^2\)[/tex] terms: [tex]\(45x^2 - 24x^2 = 21x^2\)[/tex]
- The [tex]\(x\)[/tex] terms: [tex]\(-54x + 4x = -50x\)[/tex]
- The constant term: [tex]\(9\)[/tex]

Putting it all together, we have:
[tex]\[ 20x^3 + 21x^2 - 50x + 9 \][/tex]

Thus, the simplified form of the expression is:
[tex]\[ \boxed{20x^3 + 21x^2 - 50x + 9} \][/tex]

So, the correct answer is option C: [tex]\(20x^3 + 21x^2 - 50x + 9\)[/tex].