tinh gia tri bieu thuc:
a) 35,16 - 44,84 : 4 + 15,6 x 24
b) 2,75 x a + 7,25 x a , biet a = 20,11
Tính nhanh
a ) 2 /3 x 8 / 17 + 2 /3 x 5 / 17 + 2/ 3 x 4 / 17
b) 35,16 - 44,84 : 4 + 15,6 x 24
a)2/3x(8/17+5/17+4/17)=2/3x1=2/3
b)35,16-44,84:4+15,6x24=35,16-11,21+374,4=398,35
k mk nha ,chuc ban hoc tot
Tinh gia tri bieu thuc bang cach thuan tien nhat :
1. A= 20,11 x 2,4 + 1,4 x 40,22 - 10,05 x 10,4
2. B= 3/ 1x12 + 3/ 3x20 + .... + 3/ 97x9702 + 3/ 98x9900
1) \(A=20,11\times2,4+1,4\times20,11\times2-10,05\times10,4\) (tách 40,22 = 20,11 x 2)
\(=20,11\times\left(2,4+1,4\times2\right)-10,05\times10,4\)
\(=20,11\times5,2-10,05\times5,2\times2\) (tách 10,4 = 5,2 x 2)
\(=5,2\times\left(20,11-20,1\right)\)
\(=5,2\times0,01\)
\(=0,052\)
a, biet x+y=0
tinh gia tri bieu thuc : M=\(x^4-xy^3+x^3y-y^4-1\)
b, biet xyz=2 va x+y+z=0
tinh gia tri bieu thuc : M= \(\left(x+y\right)\left(y+2\right)\left(x+2\right)\)
a/ \(M=x^4-xy^3+x^3y-y^4-1\)
\(\Leftrightarrow M=x^3\left(x+y\right)-y^3\left(x+y\right)-1\)
Mà \(x+y=0\)
\(\Leftrightarrow M=x^3.0-y^3.0-1\)
\(\Leftrightarrow M=-1\)
Vậy ...
cho 2 bieu thuc:
A=(\(\sqrt{20}\) -\(\sqrt{45}\) +3\(\sqrt{5}\) ).\(\sqrt{5}\) va B=\(\dfrac{x+1-2\sqrt{x}}{\sqrt{x}-1}\) +\(\dfrac{x+\sqrt{x}}{\sqrt{x}+1}\) (Dieu kien: x>0, x khac 1
a) Rut gon bieu thuc A va B
b)Tim cac gia tri cua x de gia tri cua bieu thuc A bang 2lan gia tri B
a: \(A=\left(2\sqrt{5}-3\sqrt{5}+3\sqrt{5}\right)\cdot\sqrt{5}=2\sqrt{5}\cdot\sqrt{5}=10\)
\(B=\dfrac{\left(\sqrt{x}-1\right)^2}{\sqrt{x}-1}+\dfrac{\sqrt{x}\left(\sqrt{x}+1\right)}{\sqrt{x}+1}\)
\(=\sqrt{x}-1+\sqrt{x}=2\sqrt{x}-1\)
b: A=2B
=>\(10=4\sqrt{x}-2\)
=>\(4\sqrt{x}=12\)
=>x=9(nhận)
35,16+44,84:4-15,6
#)Giải :
35,16 + 44,84 : 4 - 15,6
= 35,16 + 11,2 - 15,6
= 46,36 - 15,6
= 30,76
#)Chúc bn học tốt :D
35,16+44,84:4-15,6
=35,16+11,21-15,6
=30,77
Học tốt
Tinh hop li neu co the
(3,25+7,35) . (6-1,2)- 2,4
35,16 -44,84 : 4 + 15,6 . 24
=10,5.4,8-2,4
=50,4-2,4
=48
=35,16-11,21+374,4
=23,95+374,4
=398,35
35,16 + 44,84 :4 - 15,6
35,16+44,84:4-15,6
=35,16+11,21-15,6
=46,37-15,6
=30,77
6/ tinh gia tri cua bieu thuc M, voi a = 119 va b = 0, biet: M = b: (119 x a + 2005) + (119 : a - b x 2005)
7/ Tinh gia tri bieu thuc a) [17/10 + 7 - 8,7 ] : [ 23/4 - 11/2 + 9/25 ] x [ 12,98 x 0,25 ] + 12,5
ai lam nhanh nhat minh tich cho
Tinh gia tri cua bieu thuc A = x6-2*x4+x3+x2-x biet x3-x=8?
Ta có: \(A=x^6-2x^4+x^3+x^2-x\)
\(\Rightarrow A=\left(x^6-2x^4+x^2\right)+\left(x^3-x\right)\)
\(\Rightarrow A=\left[\left(x^3\right)^2-2x^3x+x^2\right]+\left(x^3-x\right)\)
\(\Rightarrow A=\left(x^3-x\right)^2+\left(x^3-x\right)\)\(\left(1\right)\)
Thay \(x^3-x=8\)vào \(\left(1\right)\)ta có:
\(\Rightarrow A=8^2+8=72\)
Vậy \(A=72\)
A=x^6-2x^4+x^2+(x^3-x)
=x^6-x^4-x^4+x^2+(x^3-x)
=x^3(x^3-x)-x(x^3-x)+(x^3-x)
=(x^3-x)(x^3-x)+(x^3-x)=8.8+8=8*9=72