Simplify 3y^2+(y+7)^2-15

$3 y^{2} + {(y + 7)}^{2} - 15$

Step 1

Simplify each term.

Rewrite ${(y + 7)}^{2}$ as $(y + 7) (y + 7)$ .

$3 y^{2} + (y + 7) (y + 7) - 15$

Expand $(y + 7) (y + 7)$ using the FOIL Method.

Apply the distributive property.

$3 y^{2} + y (y + 7) + 7 (y + 7) - 15$

Apply the distributive property.

$3 y^{2} + y \cdot y + y \cdot 7 + 7 (y + 7) - 15$

Apply the distributive property.

$3 y^{2} + y \cdot y + y \cdot 7 + 7 y + 7 \cdot 7 - 15$

Simplify and combine like terms.

Simplify each term.

Multiply $y$ by $y$ .

$3 y^{2} + y^{2} + y \cdot 7 + 7 y + 7 \cdot 7 - 15$

Move $7$ to the left of $y$ .

$3 y^{2} + y^{2} + 7 \cdot y + 7 y + 7 \cdot 7 - 15$

Multiply $7$ by $7$ .

$3 y^{2} + y^{2} + 7 y + 7 y + 49 - 15$

Add $7 y$ and $7 y$ .

$3 y^{2} + y^{2} + 14 y + 49 - 15$

Step 2

Simplify by adding terms.

Add $3 y^{2}$ and $y^{2}$ .

$4 y^{2} + 14 y + 49 - 15$

Subtract $15$ from $49$ .

$4 y^{2} + 14 y + 34$