Problem
distributive property: \[ \begin{array}{l} 3\left(y^{2}-y+6\right)-14(2 y+1) \\ =3 y^{2}-3 y+18-28 y-14 \\ =3 y^{2}-3 y-28 y+18=14 \end{array} \] d) $(3 x+5)^{2}$ \[ 9 x^{2}+25 \]
Solution
Step 1 ：Expand the given expression $(3x+5)^2$ using the distributive property: $(3x+5)(3x+5) = 9x^2 + 15x + 15x + 25 = 9x^2 + 30x + 25$
Step 2 ：The simplified expression for $(3x+5)^2$ is \(\boxed{9x^2 + 30x + 25}\)
