Polynomial Division Practice

Use long division to divide the polynomial [tex]-30x^6 + 48x^5 + 50x - 80[/tex] by [tex]5x - 8[/tex]. Write your answer in standard form.

[tex]\boxed{\phantom{answer}}[/tex]



Answer :

Sure, let's go through the polynomial long division step-by-step to divide [tex]\( -30 x^6 + 48 x^5 + 50 x - 80 \)[/tex] by [tex]\( 5 x - 8 \)[/tex].

### Step-by-Step Polynomial Division:

1. Setup the Division:
Write the dividend ([tex]\( -30 x^6 + 48 x^5 + 50 x - 80 \)[/tex]) under the division bar, and the divisor ([tex]\( 5 x - 8 \)[/tex]) outside the division bar.

2. Determine the First Term of the Quotient:
Divide the leading term of the dividend ([tex]\( -30 x^6 \)[/tex]) by the leading term of the divisor ([tex]\( 5 x \)[/tex]).

[tex]\[ \frac{-30 x^6}{5 x} = -6 x^5 \][/tex]

So, the first term of the quotient is [tex]\( -6 x^5 \)[/tex].

3. Multiply and Subtract:
Multiply the entire divisor [tex]\( 5 x - 8 \)[/tex] by the first term of the quotient [tex]\( -6 x^5 \)[/tex]:

[tex]\[ -6 x^5 \cdot (5 x - 8) = -30 x^6 + 48 x^5 \][/tex]

Subtract this result from the original polynomial:

[tex]\[ (-30 x^6 + 48 x^5 + 50 x - 80) - (-30 x^6 + 48 x^5) = 50 x - 80 \][/tex]

Now, the new dividend is [tex]\( 50 x - 80 \)[/tex].

4. Determine the Next Term of the Quotient:
Divide the leading term of the new dividend ([tex]\( 50 x \)[/tex]) by the leading term of the divisor ([tex]\( 5 x \)[/tex]):

[tex]\[ \frac{50 x}{5 x} = 10 \][/tex]

So, the next term of the quotient is [tex]\( 10 \)[/tex].

5. Multiply and Subtract Again:
Multiply the entire divisor [tex]\( 5 x - 8 \)[/tex] by the next term of the quotient [tex]\( 10 \)[/tex]:

[tex]\[ 10 \cdot (5 x - 8) = 50 x - 80 \][/tex]

Subtract this result from the new dividend:

[tex]\[ (50 x - 80) - (50 x - 80) = 0 \][/tex]

Now, we have a remainder of [tex]\( 0 \)[/tex].

### Final Quotient and Remainder:

The quotient of the division is [tex]\( -6 x^5 + 10 \)[/tex], and the remainder is [tex]\( 0 \)[/tex].

Hence, the division of [tex]\( -30 x^6 + 48 x^5 + 50 x - 80 \)[/tex] by [tex]\( 5 x - 8 \)[/tex] results in:

[tex]\[ \boxed{-6x^5 + 10} \][/tex]

with a remainder of [tex]\( 0 \)[/tex].