X + 40 - 216 = 6
tìm x
a, 40%*x+x *20%=72
b, x-20%*x =216
a) \(40\%\times x+x\times20\%=72\)
\(\left(40\%+20\%\right)\times x=72\)
\(60\%\times x=72\)
\(0,6\times x=72\)
\(x=72:0,6\)
\(x=120\)
b) \(x-20\%\times x=216\)
\(x\times\left(1-20\%\right)=216\)
\(x\times80\%=216\)
\(x\times0,8=216\)
\(x=216:0,8\)
\(x=270\)
\(2^{x+1}.3^x-6^x=216\)
\(2^{x+1}.3^x-6^x=216\)
\(\Leftrightarrow2^x2.3^x-2^x.3^x=216\)
\(\Leftrightarrow\left(2.3\right)^x\left(2-1\right)=216\)
\(\Leftrightarrow6^x=216\)
\(\Leftrightarrow6^x=6^3\)
\(\Leftrightarrow x=3\)
\(2^{x+1}.3^x-6^x=216\)
\(=>2^x.2.3^x-6^x=216\)
\(=>\left(2.3\right)^x.2-6^x=216\)
\(=>6^x.2-6^x=216\)
\(=>6^x.\left(2-1\right)=216\)
\(=>6^x.1=216\)
\(=>6^x=216:1=216\)
\(=>6^x=6^3\)
\(=>x=3\)
Vậy...
\(#NqHahh\)
\(2^{x+1}\cdot3^x-6^x=216\\\Rightarrow2^x\cdot2^1\cdot3^x-6^x=216\\\Rightarrow6^x\cdot2-6^x=216\\\Rightarrow6^x\cdot(2-1)=216\\\Rightarrow6^x=216\\\Rightarrow6^x=6^3\\\Rightarrow x=3\)
162:x+216:x=6
162:x + 216:x = 6
(162 + 216):x = 6
378:x = 6
x = 378 : 6
x= 63
\(162\div x+216\div x=6\)
\(\Leftrightarrow\) \(\left(162+216\right)\div x=6\)
\(\Leftrightarrow\) \(378\div x=6\)
\(\Leftrightarrow\) \(x=378\div6\)
\(\Leftrightarrow\) \(x=63\)
Vậy : x là 63
#Satan_Dilys
#12/7/2020_8:09
2^x+1.3^x-6^x=216
TÍNH NHANH:
A= 72 + 139 + 195 + 216
B=54 x 63 + 54 x 67 - 54 x 40
A = 72+139+195+216
=622
B=54 x 63 + 54 x 67 - 54 x 40
= 54 x ( 63+67-40)
= 54 x 90 = 4860
A=72+139+195+216
A=(72+139)+(195+216)
A=211+411)
A=622
B=54x63+54x67-54x40
B=54x(63+67-40)
B=54x90
4860
2^(x+1)×3^x-6^x=216
tìm x
(\(\dfrac{6}{5}\))\(^x\)=\(\dfrac{216}{125}\)
\(\left(\dfrac{6}{5}\right)^x=\left(\dfrac{6}{5}\right)^3\Leftrightarrow x=3\)
Vậy \(x=3\)
2^(x+1)×3^x-6^x=216
36 nhỏ hơn 6 mũ x nhân 6 nhỏ hơn hoặc bằng 216
`@` `\text {Ans}`
`\downarrow`
\(36< 6^x\times6\le216\)
`=>`\(6^2< 6^{x+1}\le6^3\)
Vì `6^2 <`\(6^{x+1}\) `=> x \ne 0; 1`
`=> x+1 \le 3`
`=> x = 3 - 1`
`=> x = 2`
Vậy, `x=2.`
\(36< 6^x\times6\le216\)
=> \(6< 6^x\le36\)
=> \(6^1< 6^x\le6^2\)
=> \(x=2\)