Question

Factor completey x^2+7x-18

Answer 1

`\huge\boxed{\sf (x - 9)(x + 2)}`

Explanation:

Given expression:

x² + 7x - 18

Using mid-term break formula.

• Multiply the side terms. [-18 × x² = -18x²]
• Now, split the mid-term in such two factor, such that multiplying both gives the side terms.
• We can split -7x (mid term) into -9x + 2x since -9x × 2x = -18x²

So,

= x² - 9x + 2x - 18

Now, take x from (x² - 9x) and 2 from (2x - 18) common

= x(x - 9) + 2(x - 9)

Take (x - 9) common

= (x - 9)(x + 2)

`\rule[225]{225}{2}`