rút gọn các biểu thức
a)25.32 / 23.3
b)53.6 / 5.22
c)8.52- 8.42 / 22.32
d)74.22+ 74.3 / 49.26
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`a) (2^5 .3^2)/(2^3 .3)`
`= (2^2 .3)/1`
`= 4.3`
`=12`
`b) (5^3 .6)/(5.2^2)`
`= (5^3 .2.3)/(5.2^2)`
`= (5^2 .3)/2`
`= 75/2`
`c) (8.5^2-8.4^2)/(2^2 .3^2)`
`= (8.(5^2-4^2))/(4.9)`
`= (8.9)/(4.9)`
`= (2.4.9)/(4.9)`
`=2`
`d) (7^4 .2^2+7^4 .3)/(49.26)`
`= (7^4.(2^2+3))/(7^2 .26)`
`= (7^4 .7)/(7^2 .26)`
`= (7^5)/(7^2. 26)`
`= (7^3)/26`
`= 343/26`
đây mà là toán lớp 5????????
Toán lớp 6 chứ
'Lớp 5 còn chưa học số mũ mà'
bn bị lag à
Ta có: \(A=\sqrt{27}-2\sqrt{12}-\sqrt{75}\)
\(=3\sqrt{3}-2\cdot2\sqrt{3}-5\sqrt{3}\)
\(=-6\sqrt{3}\)
\(\Rightarrow A=3\sqrt{3}-2\cdot2\sqrt{3}-5\sqrt{3}=-4\sqrt{3}\)
\(A=\left(5a-5\right)^2+10\left(a-3\right)\left(1+a\right).3a\)
\(A=25a^2-50a+25+30a\left(a-3+a^2-3a\right)\)
\(A=25a^2-50a+25+30a^2-90a+30a^3-90a^2\)
\(A=30a^3-35a^2-140a+25\)
Ta có: \(A=\left(5a-5\right)^2+10\left(a-3\right)\left(a+1\right)\cdot3a\)
\(=25a^2-50a+25+30a\left(a^2-2a-3\right)\)
\(=25a^2-50a+25+30a^3-60a^2-90a\)
\(=30a^3-35a^2-140a+25\)
a) Ta có: \(\left(x+1\right)^2-\left(x-1\right)^2-3\left(x+1\right)\left(x-1\right)\)
\(=x^2+2x+1-x^2+2x-1-3\left(x^2-1\right)\)
\(=4x-3x^2+3\)
\(=-3x^2+4x+3\)
b) Ta có: \(5\left(x+2\right)\left(x-2\right)-\dfrac{1}{2}\left(6-8x\right)^2+17\)
\(=5\left(x^2-4\right)-\dfrac{1}{2}\left(64x^2-96x+36\right)+17\)
\(=5x^2-20-32x^2+48x-16+17\)
\(=-27x^2+48x-19\)
Bài 1:
\(\dfrac{x^2-3}{x+\sqrt{3}}=\dfrac{\left(x+\sqrt{3}\right)\left(x-\sqrt{3}\right)}{x+\sqrt{3}}=x-\sqrt{3}\)
Bài 2:
a) Ta có: \(A=\sqrt{16x+16}-\sqrt{9x+9}+\sqrt{4x+4}+\sqrt{x+1}\)
\(=4\sqrt{x+1}-3\sqrt{x+1}+2\sqrt{x+1}+\sqrt{x+1}\)
\(=4\sqrt{x+1}\)
b) Để A=16 thì \(\sqrt{x+1}=4\)
\(\Leftrightarrow x+1=16\)
hay x=15
\(A=\dfrac{x^2-2x-3-x^2+x-1+4x+4}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(=\dfrac{3x}{\left(x+1\right)\left(x^2+x+1\right)}\)
Giải:
a,\(\dfrac{2^5.3^2}{2^3.3}=2^2.3=12\)
b, \(\dfrac{5^3.6}{5.2^2}=\dfrac{5^3.2.3}{5.2^2}=\dfrac{5^2.3}{2}=37,5\)
c, \(\dfrac{8.5^2-8.4^2}{2^2.3^2}=\dfrac{8.\left(5^2-4^2\right)}{2^2.3^2}=\dfrac{8.9}{4.9}=2\)
d, \(\dfrac{7^4.2^2+7^4.3}{49.26}=\dfrac{7^4.\left(2^2+3\right)}{7^2.26}=\dfrac{7^4.7}{7^2.26}=\dfrac{343}{26}\)
Have a nice day!
a/ \(\dfrac{2^5\cdot3^2}{2^3\cdot3}=2^2\cdot3=12\)
b/ \(\dfrac{5^3\cdot6}{5\cdot2^2}=\dfrac{5^2\cdot6}{2^2}=\dfrac{150}{4}=37.5\)
c/ \(\dfrac{8\cdot5^2-8\cdot4^2}{2^2\cdot3^2}=\dfrac{200-2048}{36}=-\dfrac{1848}{36}\)