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c) 2x+(15-(7-4)2)=24.3
2x+(15-32)=16.3
2x+(15-9)=48
2x+6=48
2x=48-6
2x=42
x=42:2
x=21
Vậy...
a, 17+(-x)=-16-(-34)
<=> 17+(-x)= - 50
=> -x= - 33
=> x= 33
b, x-40=9.(-5)+9
<=> x-40= -36
=> x= 4
c, 2x + [ 15 - ( 7 - 4 ) 2 ] = 24 . 3
<=> 2x+ [ 15- 32 ] = 48
<=> 2x+4=48
=>2x=44
=>x=22
d, 1125-10x-3 = 152 - 102
=> 1125 - 10x-3 = 125
=> 10x-3 = 1000
=> 10x-3= 103
=> x-3=3
=>x=6
a) Đặt \(A=1+2+2^2+2^3+...+2^{100}\)
\(\Rightarrow2A=2+2^2+2^3+2^4+...+2^{101}\)
\(\Rightarrow2A-A=A=\left(2+2^2+2^3+2^4+...+2^{101}\right)-\left(1+2+2^2+2^3+...+2^{100}\right)\)
\(\Rightarrow A=2^{101}-1\)
Vậy \(A=2^{101}-1\)
b) Đặt \(B=1+3+3^2+3^3+...+3^{100}\)
\(\Rightarrow3B=3+3^2+3^3+3^4+...+3^{101}\)
\(\Rightarrow3B-B=2B=\left(3+3^2+3^3+3^4+...+3^{101}\right)-\left(1+3+3^2+3^3+...+3^{100}\right)\)
\(\Rightarrow2B=3^{101}-1\)
\(\Rightarrow B=\frac{3^{101}-1}{2}\)
Vậy \(B=\frac{3^{101}-1}{2}\)
_Chúc bạn học tốt_
a) \(\frac{3^2.2^4}{8.3^2}=\frac{3^2.2^4}{2^3.3^2}=2\)
b)\(\frac{84.45}{49.54}=\frac{2^2.7.3^3.5}{7^2.2.3^3}=\frac{10}{7}\)
c) \(\frac{36.10.21}{2^3.63.35}=\frac{2^3.3^3.5.7}{2^3.3^2.5.7^2}=\frac{3}{7}\)
d) \(\frac{16.29-32}{16.37+32}=\frac{16.29-16.2}{16.37+2.16}=\frac{16.\left(29-2\right)}{16.\left(37+2\right)}=\frac{27}{39}=\frac{9}{13}\)
\(2^x=16\)
\(2^x=2^4\)
\(\Rightarrow x=4\)
-----------------------------
\(x^{50}=x\)
\(\Rightarrow x^{50}=0^{50}\)hoặc \(x^{50}=1^{50}\)
\(\Rightarrow x=0\)hoặc \(x=1\)
a )
VP=(a+b)3−3ab(a+b)VP=(a+b)3-3ab(a+b)
=a3+3a2b+3ab2+b3−3a2b−3ab2=a3+3a2b+3ab2+b3-3a2b-3ab2
=a3+b3=VT(đpcm)=a3+b3=VT(đpcm)
b)
b) Ta có
`VT=a3+b3+c3−3abc`
`=(a+b)3−3ab(a+b)+c3−3abc`
`=[(a+b)3+c3]−3ab(a+b+c)`
`=(a+b+c)[(a+b)2+c2−c(a+b)]−3ab(a+b+c)`
`=(a+b+c)(a2+b2+2ab+c2−ac−bc−3ab)`
`=(a+b+c)(a2+b2+c2−ab−bc−ca)=VP`
a)abc-3abc-2abc
=(1-3-2).abc
=-4abc
b)x2 + 3x2 - 4x2 - 5x2
=(1+3-4-5).x\(^2\)
=-5x\(^2\)