Question

Please help me please

Answer 1

Answer:

3) $x^{2}$ + 4x - 21

Step-by-step explanation:

(x - 3)(x + 7)

Distribute:

x(x + 7)

-3(x + 7)

x(x) = $x^{2}$

x(7) = 7x

-3(x) = -3x

-3(7) = -21

Combine like terms:

7x - 3x = 4x

Put it together:

$x^{2}$ + 4x - 21

Answer 2

Answer: x²+ 4x - 21

Let's do this step-by-step.

1. Apply the foil method. (formula: (a + b)(c + d) = ac + ad + bc + bd)

F - First

O - Outer

I - Inner

L - Last

= xx + x × 7 + (-3)x + (-3) × 7

2. Apply the minus and plus rules. + (-a) = -a

xx + 7x - 3x - 3 × 7

3. Simplify.

• Convert xx into a exponent.

• xx ⇒ x²

• Subtract 7 by 3.

• 7x - 3x = 4x

• Multiply 3 by 7.
• 7 × 3 = 21

Hence, the answer is x² + 4x - 21

Let me know if you have any questions.

~ Lily, from Brainly.