Em cảm ơn cô ạ.

\(\left(3+\sqrt{5}\right)\sqrt{\left(\sqrt{5}-3\right)^2}\\ =\left(3+\sqrt{5}\right)\left|\sqrt{5}-3\right|\\ =\left(3+\sqrt{5}\right)\left(3-\sqrt{5}\right)\\ =9-5=4\)

\(n_{NaOH}=\dfrac{8}{40}=0,2\left(mol\right)\\ n_{CuSO_4}=0,225\cdot0,4=0,09\left(mol\right)\\ 2NaOH+CuSO_4\rightarrow Cu\left(OH\right)_2+Na_2SO_4\\ n_{\text{NaOH pư}}=2n_{CuSO_4}=2\cdot0,09=0,18\left(mol\right)\\ n_{Na_2SO_4}=n_{Cu\left(OH\right)_2}=0,09\left(mol\right)\\ n_{\text{NaOH dư}}=0,2-0,18=0,02\left(mol\right)\\ C_{M_{Na_2SO_4}}=\dfrac{0,09}{0,4}=0,225\left(M\right)\\ C_{M_{\text{NaOH dư}}}=\dfrac{0,02}{0,4}=0,05\left(M\right)\)

Because of his deep love for her, he can't live without her.

Because of the heavy rain, we had to put off the light.

In spite of the good jobs he got, he was not satisfied.

Despite telling lies, many people believe him.

Trích mẫu thử.

Hòa tan các mẫu thử vào nước dư rồi cho quỳ tím vào mỗi dung dịch.

Dung dịch nào làm quỳ chuyển xanh thì chất rắn ban đầu là BaO.

Dung dịch nào làm quỳ chuyển đỏ thì chất rắn ban đầu là P₂O₅.

\(x^2+x=0\\ \Leftrightarrow x\left(x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)

thiếu trường hợp rồi ạ!

\(\left(x-3\right)^2=25\\ \Leftrightarrow\left[{}\begin{matrix}x-3=5\\x-3=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=8\\x=-2\end{matrix}\right.\)