thuc hien phep tinh
125 (28+72 ) - 25 (3^2 .4 +64 )
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\(9!-8!-7!.8^2\)
\(=8!.9-8!-7!.8.8\)
\(=8!\left(9-1\right)-8!.8\)
\(=8!-8!\)
\(=0\)
\(5\left[\left(85-35:7\right):2^3+3^2.10\right]-50\)
\(=5\left[\left(85-5\right):8+9.10\right]-50\)
\(=5\left[80:8+90\right]-50\)
\(=5\left[10+90\right]-50\)
\(=5.100-50\)
\(=500-50\)
\(=450\)
\(2^3-5^3:5^2+12.2^2\)
\(=8-5+12.4\)
\(=8-5+48\)
\(=3+48\)
\(=51\)
_Chúc bạn học tốt_
1.
a) (—7/3)3:(—7/3)2=(—7/3)3–2=—7/3
b) (—4/9):(—4/9)3= (—4/9)1–3=(—4/9)—2=81/16
c) (1/5)10:(1/5)7=(1/5)10–7=(1/5)3=1/125
2.
a) —x/7 =1/—21
==> —x.(—21)=7.1
==> —x.(—21)=7
==> —x=7:(—21)
==> —x=—1/3
==> x=1/3
b) 4 2/5 . 0,5–1 3/7= 22/5 . 1/2 —10/7= 22.1/5.2–10/7= 11/5 —10/7= 77/35 — 50/35= 27/35
c) 3x2–2x=0
==> x3(3–2)=0
x3.1=0
x3=0:1
x3=0
==> x=0
c) 9x2–1=0
9x2=0+1
9x2=1
x2=1:9
x2=1/9
x2=12/32 hoặc x2=(—1/3)2
Vậy x=1/3 hoặc x=—1/3
\(125.\left(28+72\right)-25.\left(3^2.4+64\right)\)
\(=125.100-25.\left(9.4+64\right)\)
\(=125.100-25.\left(36+64\right)\)
\(=125.100-25.100\)
\(=100.\left(125-25\right)\)
\(=100.100\)
\(=10000\)
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