Question

помогите, пожалуйста.

Answer 1

$1) \ (x-3)^{2}+x\cdot (2x-1)=x^{2}-2\cdot x\cdot 3+3^{2}+x\cdot 2x-x\cdot 1= \\\\=x^{2}-6x+9+2x^{2}-x=3x^{2}-7x+9\\\\x=2 \ \Rightarrow \ 3x^{2}-7x+9=3\cdot 2^{2}-7\cdot 2+9=12-14+9=\boxed7\\\\\\2) \ (5-x)(x+5)=5^{2} -x^{2}=25-x^{2} \\\\x=2 \ \Rightarrow \ 25-x^{2} =25-2^{2}=25-4=\boxed{21}$