1)thuc hien phep tinh sau
a) A=54+(-72)+65+31+(-28)+120
thuc hien phep tinh
125 (28+72 ) - 25 (3^2 .4 +64 )
\(125.\left(28+72\right)-25.\left(3^2.4+64\right)\)
\(=125.100-25.\left(9.4+64\right)\)
\(=125.100-25.\left(36+64\right)\)
\(=125.100-25.100\)
\(=100.\left(125-25\right)\)
\(=100.100\)
\(=10000\)
125.(28+72)-25.(3^2.4+64)
=125.100-25.(9.4+64)
=125.100-25.(36+64)
=125.100-25.100
=100.(125-25)
=100.100
=100^2
=10 000
thuc hien phep tinh :
a) 28/11 . 21/22 . 9
a) \(\dfrac{28}{11}\cdot\dfrac{21}{22}\cdot9\)
\(=\dfrac{28\cdot21}{11\cdot22}\cdot9\)
\(=\dfrac{14\cdot21}{11\cdot11}\cdot9\)
\(=\dfrac{294}{121}\cdot9\)
\(=\dfrac{2646}{121}\)
Thuc hien phep tinh 1 cach hop li
a, 120 - ( 61) × (-2)^3 × ( -1)^ 2n ( n thuoc N*)
b, 136 × (-47) +36 × 47
c, (-48) + 72 +36 + (-304)
b) \(=-47\left(136-36\right)\)
=\(-47.100=-4700\)
Thuc hien phep tinh 1 cach hop li
a, A = 120 - ( 61) × (-2)^3 × ( -1)^ 2n ( n thuoc N*)
b, B = 136 × (-47) +36 × 47 - (-1)^n (n le)
c, C = (-48) + 72 +36 + (-304)
a: A=120-61x(-8)
=120+488=608
b: =47(-136+36)-(-1)
=-4700+1=-4699
c: C=(-48-304+72)+36
=-352+72+36
=-280+36=-244
Khong thuc hien phep tinh de tim ket qua. Hay chung minh rang cac tong sau lon hon 1
N = \(\frac{21}{90}+\frac{31}{72}+\frac{21}{40}+\frac{-1}{45}+\frac{-1}{50}\)
Khong thuc hien phep tinh de tim ket qua. Hay chung minh rang tong sau lon hon 1
N = \(\frac{21}{90}+\frac{31}{72}+\frac{21}{40}+\frac{-1}{45}+\frac{-1}{50}\)
Thuc hien phep tinh
A/-120 - 18×(-5+6)
B/465+(-38)+(-465)+10+(-42)
A, ( - 120 ) - 18 x ( - 5 + 6 )
= ( - 120 ) - 18 x 1
= ( - 120 ) - 18
= - 138
B, 465 + ( - 38 ) + ( - 465 ) + 10 + ( - 42 )
= 0 + ( - 38 ) + 10 + ( - 42 )
= ( - 80 ) + 10
= - 70
thuc hien phep tinh( hop ly neu co the):
a) (11+159) . 37+(185-31) :14
b) 3280-(3^2.7^3.49)
a) (11+159).37+(185-31):14
=170.37+154:14
=6290+11
=6301
câu b bạn viết khó hiểu quá bạn viết lại đầu bài đi mik giải cho
Thuc hien phep tinh :
\(\frac{28^{15}.3^{17}}{84^{16}}\)
\(\frac{28^{15}\cdot3^{17}}{84^{16}}\)
\(=\frac{4^{15}\cdot7^{15}\cdot3^{17}}{4^{16}\cdot7^{16}\cdot3^{16}}\)
\(=\frac{4\cdot1\cdot3}{1\cdot7\cdot1}\)
\(\frac{12}{7}\)