Câu 58: Trang 32 - sách giáo khoa (SGK) toán lớp 9 tập 1Rút gọn các biểu thức sau :a....

{
"content1": "a. $5\sqrt{\frac{1}{5}}+\frac{1}{2}\sqrt{20+\sqrt{5}}$",
"content2": "Simplify the expression: $5\sqrt{\frac{1}{5}}+\frac{1}{2}\sqrt{20+\sqrt{5}}$",
"content3": "We have: $5\sqrt{\frac{1}{5}} = 5\sqrt{\frac{1}{5}} = 5 \times \frac{1}{\sqrt{5}} = 5\sqrt{5}$",
"content4": "Substitute the value back in, we get: $5\sqrt{5} + \frac{1}{2}\sqrt{20+\sqrt{5}}$"
}

{
"content1": "b. $\sqrt{\frac{1}{2}}+\sqrt{4,5}+\sqrt{12,5}$",
"content2": "Simplify the expression: $\sqrt{\frac{1}{2}}+\sqrt{4,5}+\sqrt{12,5}$",
"content3": "We have: $\sqrt{\frac{1}{2}} = \frac{1}{\sqrt{2}} = \frac{\sqrt{2}}{2}$",
"content4": "Substitute the value back in, we get: $\frac{\sqrt{2}}{2} + \sqrt{4.5} + \sqrt{12.5}$"
}

{
"content1": "c. $\sqrt{20}-\sqrt{45}+3\sqrt{18}+\sqrt{72}$",
"content2": "Simplify the expression: $\sqrt{20}-\sqrt{45}+3\sqrt{18}+\sqrt{72}$",
"content3": "We have: $\sqrt{20} = \sqrt{4 \times 5} = 2\sqrt{5}$",
"content4": "Substitute the value back in, we get: $2\sqrt{5} - \sqrt{45} + 3\sqrt{18} + \sqrt{72}$"
}

{
"content1": "d. $0,1\sqrt{200}+2\sqrt{0,08}+0,4\sqrt{50}$",
"content2": "Simplify the expression: $0.1\sqrt{200}+2\sqrt{0.08}+0.4\sqrt{50}$",
"content3": "We have: $0.1\sqrt{200} = 0.1 \times 10\sqrt{2} = \sqrt{2}$",
"content4": "Substitute the value back in, we get: $\sqrt{2} + 2\sqrt{0.08} + 0.4\sqrt{50}$"
}