a) 89,42 + [ 21,15 + 16,471]=

b) [ 135,8 + 69,07] + 52,18=

c) [ 89,42 + 21,15 ] + 16,471=

d) 135,8 + [ 69,07 + 52,18]=

Tinh gia tri bieu thuc:a.3^2^3^0 b.5^2^0^3

cho 2 bieu thuc:A=101 x50 ;B= 50x49+53x50

khong thuc hien tinh hay su dung tinh chat cua phep tinh de so sanh gia tri so cua A va B

Tính nhanh:

99,40 - 89,42 - 9,40

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

tinh gia tri cua bieu thuc:a, nam phan tam cong ba phan tam chia hai phan ba bang

                                    b, mot phan bay muoi hai nhan mot tram bon muoi bon phan hai muoi ba cong mot phan bon muoi sau

cho \(\frac{x}{a}+\frac{y}{b}+\frac{z}{c}=2\)  ;\(\frac{a}{x}+\frac{b}{y}+\frac{c}{z}=2\)

tinh gia tri bieu thuc:A=\(\left(\frac{a}{x}\right)^2+\left(\frac{b}{y}\right)^2+\left(\frac{c}{z}\right)^2\)

cho a>0;b>0va a+b\(\le\)\(4\)

tim gia tri nho nhat cua bieu thuc:A=\(\frac{2}{a^2+b^2}+\frac{35}{ab}+2ab\)

cho a R b =a*b/ a+b . Tinh gia tri bieu thuc cua : 13R7 - 12r4 . TINH gia tri cua bieu thuc tren ( 30 giay )