Simplify each of the expressions.

[tex]\[
\begin{array}{l}
\left(6 y^2 + 4 y + 5 \right) - \left(3 - 7 y + y^2 \right) \\
= \square y^2 + \square y + \square \\
\end{array}
\][/tex]

[tex]\[
(x-7)(x+3) = \square
\][/tex]



Answer :

Sure, let's simplify each of the given expressions step by step.

### Simplifying [tex]\((6y^2 + 4y + 5) - (3 - 7y + y^2)\)[/tex]

1. Distribute the negative sign to each term in the second parentheses:
[tex]\[ 6y^2 + 4y + 5 - 3 + 7y - y^2 \][/tex]

2. Combine like terms:
- Combine the [tex]\(y^2\)[/tex] terms:
[tex]\[ 6y^2 - y^2 = 5y^2 \][/tex]
- Combine the [tex]\(y\)[/tex] terms:
[tex]\[ 4y + 7y = 11y \][/tex]
- Combine the constant terms:
[tex]\[ 5 - 3 = 2 \][/tex]

3. Write the simplified expression:
[tex]\[ 5y^2 + 11y + 2 \][/tex]

So, the simplified expression is:
[tex]\[ \boxed{5y^2 + 11y + 2} \][/tex]

### Simplifying [tex]\((x-7)(x+3)\)[/tex]

1. Apply the distributive property (FOIL method):
- First, [tex]\(x \cdot x = x^2\)[/tex]
- Outer, [tex]\(x \cdot 3 = 3x\)[/tex]
- Inner, [tex]\(-7 \cdot x = -7x\)[/tex]
- Last, [tex]\(-7 \cdot 3 = -21\)[/tex]

2. Combine like terms:
[tex]\[ x^2 + 3x - 7x - 21 \][/tex]
- Combine the [tex]\(x\)[/tex] terms:
[tex]\[ 3x - 7x = -4x \][/tex]

3. Write the simplified expression:
[tex]\[ x^2 - 4x - 21 \][/tex]

So, the simplified expression is:
[tex]\[ \boxed{x^2 - 4x - 21} \][/tex]