To divide the polynomial \( 15x^2 + 14x - 8 \) by \( 3x + 4 \) using long division, we will follow these steps:
-
Setup the division: We write \( 15x^2 + 14x - 8 \) (the dividend) under the long division symbol and \( 3x + 4 \) (the divisor) outside.
-
Divide the leading term: We start by dividing the leading term of the dividend \( 15x^2 \) by the leading term of the divisor \( 3x \).
\[ \frac{15x^2}{3x} = 5x \]
-
Multiply and subtract: Next, we multiply \( 5x \) by the entire divisor \( 3x + 4 \):
\[ 5x(3x + 4) = 15x^2 + 20x \]
Now we subtract \( (15x^2 + 20x) \) from the original polynomial:
\[ (15x^2 + 14x - 8) - (15x^2 + 20x) = 14x - 20x - 8 = -6x - 8 \]
-
Bring down the next term: Since we only have the remainder \( -6x - 8 \) at this point, we don't need to bring down anything (as there are no remaining terms to bring down).
-
Repeat the process: Now, we divide the new leading term \( -6x \) by \( 3x \):
\[ \frac{-6x}{3x} = -2 \]
-
Multiply and subtract again: We multiply \( -2 \) by the entire divisor:
\[ -2(3x + 4) = -6x - 8 \]
Now, subtract \( (-6x - 8) \) from the current remainder \( -6x - 8 \):
\[ (-6x - 8) - (-6x - 8) = 0 \]
-
Conclusion: There is no remainder, and the division is complete. Our final quotient is:
\[ \boxed{5x - 2} \]