Question

7класс Спростить виразі ​

Answer 1

$\displaystyle\bf\\5)\\\\x(x-2)-(x-3)^{2} =x\cdot x-x\cdot 2-(x^{2} -2\cdot x\cdot 3+3^{2} )=\\\\\\=x^{2} -2x-(x^{2} -6x+9)=x^{2} -2x-x^{2} +6x-9=\\\\\\=\underbrace{(x^{2} -x^{2} )}_{0}+\underbrace{(6x-2x)}_{4x}-9=4x-9\\\\6)\\\\0,3(3kp-2)^{2} +0,8(2kp+1)=\\\\\\=0,3\cdot\Big[(3kp)^{2} -2\cdot 3kp\cdot 2+2^{2} \Big]+0,8\cdot 2kp+0,8\cdot 1=\\\\\\=0,3\cdot(9k^{2} p^{2} -12kp+4)+1,6kp+0,8=$

$\displaystyle\bf\\=2,7k^{2} p^{2} -3,6kp+1,2+1,6kp+0,8=\\\\\\=2,7k^{2} p^{2} +\underbrace{(1,6kp-3,6kp)}_{-2kp}+\underbrace{(1,2+0,8)}_{2}=2-2kp$