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\(c.6,7\times9,3+3,3\times9,3\)
\(=9,3\times\left(6,7+3,3\right)=9,3\times10=93\)
\(d.5,5\times-4,5\times4,7\)
\(=4,7\times\left(5,5-4,5\right)=4,7\times1=4,7\)
\(e.5,6\times4+5,6\times3+5,6\times2+5,6\)
\(=5,6\times\left(4+3+2+1\right)=5,6\times10=56\)
=5,6x(4+3+1)
=5,6x8
=44,83
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7,89x(54-52-89)
=7,89x-87
=-686,43
5,6 x 4 + 5,6 x 3 + 5,6 x 2 + 5,6 = 5,6 x 4 + 5,6 x 3 + 5,6 x 2 + 5,6 x 1 = 5,6 x (4 + 3 + 2 +1) = 5,6 x 10 = 56
7,89 x 54 - 7,89 x 52 - 7,89 = 7,89 x 54 - 7,89 x 52 - 7,89 x 1 = 7,89 x (54 - 52 - 1) = 7,89 x 1 = 7,89.
A = (30: 7\(\dfrac{1}{2}\)) : (\(\dfrac{1}{15}\):0,5) -1,5\(\times\)(4\(\dfrac{1}{2}\)-\(\dfrac{9}{2}\))
A = (30 : \(\dfrac{15}{2}\)): (\(\dfrac{1}{15}\) \(\times\) 2) - 1,5 \(\times\) (\(\dfrac{9}{2}\) - \(\dfrac{9}{2}\))
A = (30 \(\times\) \(\dfrac{2}{15}\)) : \(\dfrac{2}{15}\) - 1,5 \(\times\) 0
A = 4 \(\times\) \(\dfrac{15}{2}\) - 0
A = 30
\(x\times2+15=1,5\times\left(x+20\right)\)
\(x\times2+15=1,5\times x+30\)
\(\Rightarrow x\times2-1,5\times x=30-15\)
\(x\times\left(2-1,5\right)=15\)
\(x\times0,5=15\)
\(x=15:0,5\)
\(x=30\)
\(x\times2+15=1,5\times\left(x+20\right)\)
\(\Rightarrow x\times2+15=1,5\times x+\left(1,5\times20\right)\)
\(\Rightarrow x\times2+15=1,5\times x+30\)
\(\Rightarrow1,5\times x-x\times2=15-30\)
\(\Rightarrow\left(1,5-2\right)\times x=-15\)
\(\Rightarrow-0,5\times x=-15\)
\(\Rightarrow x=-15:-0,5\)
\(\Rightarrow x=30\)
Vậy x = 30
_Chúc bạn học tốt_
1.5x2=3
5.6x4=22.4
2.3x7=16.1
1,5x 2=3
5,6x4=22,4
2,3x7=16,1
Tk nha! Kb nha!