don gian cac bieu thuc
(xcany + ycanx).(canx-cany)/ can xy
Những câu hỏi liên quan
don gian cac bieu thuc
can (2 + can 3) - can(2 - can 3)
đặt A=\(\sqrt{2+\sqrt{3}}-\sqrt{2-\sqrt{3}}\)
=>\(\sqrt{2}A=\sqrt{2}\sqrt{2+\sqrt{3}}-\sqrt{2}\sqrt{2-\sqrt{3}}\)
=\(\sqrt{2\left(2+\sqrt{3}\right)}-\sqrt{2\left(2-\sqrt{3}\right)}=\sqrt{4+2\sqrt{3}}-\sqrt{4-2\sqrt{3}}\)
=\(\sqrt{3+2\sqrt{3}.1+1}-\sqrt{3-2\sqrt{3}.1+1}\)
=\(\sqrt{\left(\sqrt{3}+1\right)^2}-\sqrt{\left(\sqrt{3}-1\right)^2}=\sqrt{3}+1-\left(\sqrt{3}-1\right)\)
=\(\sqrt{3}+1-\sqrt{3}+1=2\)
=>A=\(\frac{2}{\sqrt{2}}=\frac{\sqrt{2}\sqrt{2}}{\sqrt{2}}=\sqrt{2}\)
vậy \(\sqrt{2+\sqrt{3}}-\sqrt{2-\sqrt{3}}=\sqrt{2}\)
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cho cac bieu thuc sau:xyx,x3y,-11xy2,3x2y,-7yx3,4(xy)2 hay xep cac don thuc da cho thanh cac nhom don thuc dono dang
Cho don thuc A= -xy2 , B=5xy3z, C=5xy2
a, Tim cac so nguyen x de bieu thuc M= \(\dfrac{3}{7-x}\) dat gia tri lon nhat
tim cac so m,n,p thoa man : m+n+p+8=2canm-1 + 4cann-2 +6canp-3
tim cac so x,y,z thoa man :canx+cany-1 +canz-2 = 1/2(x+y+z)
tim cac so x,y,z thoa man :x+y+z+4=2canx-2 +4cany-3+6canz-5
Cho bieu thuc A = 3/n-2
a) Tim cac so nguyen n de bieu thuc A la phan so
b) Tim cac so nguyen n de A la mot so nguyen
Cac giup minh nhe minh dang can gap.
viet cac bieu thuc sau duoi dang tong:
a,(4-xy)^3
b,(0,1+xy)^3
\(a,\left(4-xy\right)^3\)
\(=4^3-3.4^2xy+3.4.x^2y^2-x^3y^3\)
\(=64-48xy+12x^2y^2-x^3y^3\)
\(b,\left(0,1+xy\right)^3\)
\(=\left(0,1\right)^3+3.\left(0,1\right)^2xy+3.0,1.\left(xy\right)^2+x^3y^3\)
\(=0,001+0,03xy+0,3x^2y^2+x^3y^3\)
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baif2 don gian bieu thuc
(-75)-(p+20)+95
\(\left(-75\right)-\left(p+20\right)+95\)
\(=-75-p-20+95\)
\(=-p+\left(-75+95\right)-20\)
\(=-p+20-20\)
\(=-p\)
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viet cac bieu thuc sau duoi dang binh phuong cua mot tong hoac mot hieu
xy^2+(2+xy^2)+10-6x+x^2
don gian bieu thuc khi bo ngoac
-(a-b+c)-(a+b+c)
-a-b+c-a+b+c=-a+-b+c-a+b+c
=(-a+a)+(-b+b)+(c-c)
=0+0+0
=0
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