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Use long division to divide the polynomial [tex]15x^2 + 14x - 8[/tex] by [tex]3x + 4[/tex]. What is the quotient?

A. [tex]5x + 2[/tex]
B. [tex]5x - 2 + \frac{16}{3x + 4}[/tex]
C. [tex]5x + 2 - \frac{16}{3x + 4}[/tex]
D. [tex]5x - 2[/tex]


Sagot :

Certainly! Let's perform the polynomial long division to divide [tex]\( 15x^2 + 14x - 8 \)[/tex] by [tex]\( 3x + 4 \)[/tex].

Step 1: Setup the Division

We start by writing the dividend [tex]\( 15x^2 + 14x - 8 \)[/tex] and the divisor [tex]\( 3x + 4 \)[/tex]:

[tex]\[ \frac{15x^2 + 14x - 8}{3x + 4} \][/tex]

Step 2: Divide the Leading Terms

Divide the leading term of the dividend [tex]\( 15x^2 \)[/tex] by the leading term of the divisor [tex]\( 3x \)[/tex]:

[tex]\[ \frac{15x^2}{3x} = 5x \][/tex]

So, the first term of the quotient is [tex]\( 5x \)[/tex].

Step 3: Multiply and Subtract

Multiply [tex]\( 5x \)[/tex] by the divisor [tex]\( 3x + 4 \)[/tex]:

[tex]\[ 5x \cdot (3x + 4) = 15x^2 + 20x \][/tex]

Subtract this from the original dividend:

[tex]\[ (15x^2 + 14x - 8) - (15x^2 + 20x) = (14x - 20x) - 8 = -6x - 8 \][/tex]

Step 4: Divide the Remaining Terms

Now, divide the leading term [tex]\( -6x \)[/tex] by the leading term [tex]\( 3x \)[/tex]:

[tex]\[ \frac{-6x}{3x} = -2 \][/tex]

So, the next term of the quotient is [tex]\( -2 \)[/tex].

Step 5: Multiply and Subtract

Multiply [tex]\( -2 \)[/tex] by the divisor [tex]\( 3x + 4 \)[/tex]:

[tex]\[ -2 \cdot (3x + 4) = -6x - 8 \][/tex]

Subtract this from the current remainder:

[tex]\[ (-6x - 8) - (-6x - 8) = 0 \][/tex]

Since the remainder is 0, we have completed the division.

Step 6: Write the Quotient

The quotient of the polynomial division is:

[tex]\[ 5x - 2 \][/tex]

Final Answer:

The quotient of dividing [tex]\( 15x^2 + 14x - 8 \)[/tex] by [tex]\( 3x + 4 \)[/tex] is [tex]\( 5x - 2 \)[/tex].

Therefore, the correct choice is:

[tex]\[ \boxed{5x - 2} \][/tex]