7x^2+2x-9/7x+9+(x+2)(x-3)

1 answer

To simplify the expression \(\frac{7x^2 + 2x - 9}{7x + 9} + (x + 2)(x - 3)\), we can work through each part step by step.

First, let's simplify the quadratic expression and then evaluate the second part of the expression.

Step 1: Factor the numerator

The expression in the numerator is \(7x^2 + 2x - 9\). We will see if it can be factored. We're looking for two numbers that multiply to \(7 \times -9 = -63\) and add up to \(2\).

The factors of \(-63\) that add up to \(2\) are \(9\) and \(-7\). Therefore, we can factor the quadratic as follows:

\[ 7x^2 + 9x - 7x - 9 = (7x^2 - 7x + 9x - 9) \]

Grouping:

\[ = 7x(x - 1) + 9(x - 1) = (7x + 9)(x - 1) \]

Thus, the numerator can be factored as:

\[ 7x^2 + 2x - 9 = (7x + 9)(x - 1) \]

Step 2: Substitute into the original expression

Now substitute back into the original expression:

\[ \frac{(7x + 9)(x - 1)}{7x + 9} + (x + 2)(x - 3) \]

Step 3: Cancel the common term

As long as \(7x + 9 \neq 0\), we can cancel this factor:

\[ = x - 1 + (x + 2)(x - 3) \]

Step 4: Expand the second part

Next, expand \((x + 2)(x - 3)\):

\[ (x + 2)(x - 3) = x^2 - 3x + 2x - 6 = x^2 - x - 6 \]

Step 5: Combine like terms

Now substitute back into the equation:

\[ = x - 1 + (x^2 - x - 6) \]

Combine like terms:

\[ = x - 1 + x^2 - x - 6 = x^2 - 7 \]

Conclusion

Thus, the simplified form of the original expression is:

\[ \boxed{x^2 - 7} \]