Divide the following polynomials. Write the answer in descending powers of [tex]$x$[/tex].

[tex]
\left(9x^2 - 18x - 7\right) \div (3x + 1)
[/tex]



Answer :

To divide the polynomial [tex]\(9x^2 - 18x - 7\)[/tex] by [tex]\(3x + 1\)[/tex], we will use polynomial long division. Here are the steps:

### Step 1: Setup the Division

Set up the division similar to how you would with numbers, with [tex]\(9x^2 - 18x - 7\)[/tex] (the dividend) being divided by [tex]\(3x + 1\)[/tex] (the divisor).

### Step 2: Divide the Leading Terms

Divide the leading term of the dividend by the leading term of the divisor:
[tex]\[ \frac{9x^2}{3x} = 3x. \][/tex]

### Step 3: Multiply and Subtract

Multiply the entire divisor [tex]\(3x + 1\)[/tex] by [tex]\(3x\)[/tex]:
[tex]\[ 3x(3x + 1) = 9x^2 + 3x. \][/tex]

Subtract this result from the dividend:
[tex]\[ (9x^2 - 18x - 7) - (9x^2 + 3x) = -21x - 7. \][/tex]

### Step 4: Repeat the Process

Now, repeat the process with [tex]\(-21x - 7\)[/tex]:

Divide the leading term of the new dividend by the leading term of the divisor:
[tex]\[ \frac{-21x}{3x} = -7. \][/tex]

Multiply the entire divisor [tex]\(3x + 1\)[/tex] by [tex]\(-7\)[/tex]:
[tex]\[ -7(3x + 1) = -21x - 7. \][/tex]

Subtract this result from the new dividend:
[tex]\[ (-21x - 7) - (-21x - 7) = 0. \][/tex]

### Step 5: Write the Quotient

Since the remainder is 0, there is no remainder. Thus, the quotient is the result of the division:
[tex]\[ 3x - 7. \][/tex]

### Final Answer

The quotient of [tex]\(\frac{9x^2 - 18x - 7}{3x + 1}\)[/tex] is:
[tex]\[ \boxed{3x - 7}. \][/tex]