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a: =144+13,2=157,2
b: x-23,5=12,4
nên x=35,9
c: =>x:4,3=36,54
hay x=157,122
=> 1(x+2) +2(x+2) +3(x+2)+....+ 10(x+2) = 242
=> (1+2+3+...+10)X ( x+2) =242
=> 55X (x+2) =242
=> x+2 = 242 :55
=> x+2=22/5
=> x=12/ 5
( nhớ click đúng và kết bạn với tớ nha )
(x+2)+(x+2).2+(x+2).3+...+(x+2).10=242
(x+2)(1+2+3+...+10)=242
(x+2).55=242
(x+2)=242:55=4,4
=>x=4,4-2=2,2
\(\text{0,29 x 8 x 1,25 = ?}\)
\(0.29X8=2.32\)
\(2.32X1.25=\text{2.9}\)
Cách 1:
\(\left(\dfrac{1}{3}+\dfrac{2}{9}\right)\times\dfrac{4}{9}\)
\(=\dfrac{5}{9}\times\dfrac{4}{9}\)
\(=\dfrac{20}{81}\)
Cách 2:
\(\left(\dfrac{1}{3}+\dfrac{2}{9}\right)\times\dfrac{4}{9}\)
\(=\dfrac{1}{3}\times\dfrac{4}{9}+\dfrac{2}{9}\times\dfrac{4}{9}\)
\(=\dfrac{4}{27}+\dfrac{8}{81}\)
\(=\dfrac{20}{81}\)
C1: \(\left(\dfrac{1}{3}+\dfrac{2}{9}\right)\)x\(\dfrac{4}{9}\)=\(\left(\dfrac{3}{9}+\dfrac{2}{9}\right)\text{x}\dfrac{4}{9}\)=\(\dfrac{5}{9}\text{x}\dfrac{4}{9}=\dfrac{20}{81}\)
C2: \(\left(\dfrac{1}{3}+\dfrac{2}{9}\right)\)x\(\dfrac{4}{9}\)=\(\dfrac{1}{3}\text{ x}\dfrac{4}{9}+\dfrac{2}{9}\text{ x}\dfrac{4}{9}\)=\(\dfrac{4}{27}+\dfrac{8}{81}=\dfrac{12}{81}+\dfrac{8}{81}=\dfrac{20}{81}\)
a) 0,63 x 8 + 0,63 + 0,63 x 9,89
= 0.63 x ( 8+1+9.89 ) = 0.63 x 18.98 = 11.9
b) 9,89 x 99 + 9,89
= 9.89 x ( 99 + 1) = 9.89 x 100 = 989
a) 0,63 x 8 + 0,63 + 0,63 x 9,89
= 0,63 x 8 + 0,63 x 1 + 0,63 x 9,89
= 0,63 x ( 8 + 1 + 9,89 )
= 0,63 x 18,89
= 11,9007
b) 9,89 x 99 + 9,89
= 9,89 x 99 + 9,89 x 1
= 9,89 x ( 99 + 1 )
= 9,89 x 100
= 989
a) \(x\cdot3,4=\frac{1}{3}\)
\(x\cdot\frac{17}{5}=\frac{1}{3}\)
\(x=\frac{1}{3}:\frac{17}{5}\)
\(x=\frac{5}{51}\)
b) \(x:\frac{4}{5}=\frac{5}{2}\)
\(x=\frac{5}{2}\cdot\frac{4}{5}\)
\(x=2\)
c) \(\frac{2}{9}:x=\frac{2}{3}\)
\(x=\frac{2}{9}:\frac{2}{3}\)
\(x=\frac{1}{3}\)