Question

Alguém responde essa questões por favor ??????????????

Answer 1

$18)\\\sqrt{2x+7} \neq 0\\x\neq \frac{-7}{2} \\\\19)\\ f(x)=-2x+4 , f(x)=0\\2x=4\\x=2\\\\20)\\(x+1)^{2}=x+7\\x^{2} +2x+1=x+7\\x^{2} +x-6=0\\ Delta=1+24=25\\x=\frac{-1+ou-5}{2}(bhaskara)\\ x=-3 ou x=2$