2.3x=19.38-812
Tính bằng cách thuận tiện nhất
812 x 5 + 812 x 7 - 812 x 2
812x5+812x7-812x2
=812x(5+7-2)
=812x10
=8120
812 x 5 + 812 x 7 - 812 x 2
= 812 x ( 5 + 7 - 2 )
= 812 x 10
= 8120
Chúc bn hok tốt !
812 x 5 + 812 x 7 - 812 x 2
= 812 x ( 5 + 7 - 2 )
= 812 x 10
= 8120
812*5+112*7-812*2
812*5+112*7-812*2
=812*(5-2)+112*7
=812*3+784
=2436+784
=3220
4x+2.3x=16.125
`4^(x+2) .3^x = 16.12^5`
`4^(x+2) .3^x = 4^2 . (3.4)^5`
`4^(x+2) .3^x = 4^2 . 3^5. 4^5`
`4^(x+2) .3^x = 4^7 . 3^5`
`4^(x+2) .3^x = 4^(5+2) . 3^5`
`x=5`
Ta có:4x+2.3x=16.125
⇔ 4x+2.3x=417.315
⇔ 4x+2:417.3x:315=1
⇔ 4x-15.3x-15=1
⇔ 12x-15=120
⇔ x-15=0
⇔ x=15
Ta có: \(4^{x+2}\cdot3^x=16\cdot12^5\)
\(\Leftrightarrow4^x\cdot16\cdot3^x=16\cdot12^5\)
\(\Leftrightarrow12^x=12^5\)
hay x=5
2.3x=10.312+8.274
\(2.3^x=10.3^{12}+8.\left(3^3\right)^4\)
\(2.3^x=10.3^{12}+8.3^{12}\)
\(2.3^x=3^{12}.\left(10+8\right)\)
\(2.3^x=3^{12}.18\)
\(3^x=3^{12}.18:2\)
\(3^x=3^{12}.9\)
\(3^x=3^{12}.3^2\)
\(3^x=3^{14}\)
\(\Rightarrow x=14\)
2.3x=10.312+8.274
2.3x=10.312+23.312
2.3x=312.18
2.3x=312.32.2
2.3x=314.2
=>x=14
2.3x+3=10.312 + 8.312
\(2.3^{x+3}=10.3^{12}+8.3^{12}\)
\(\Leftrightarrow2.3^{x+3}=18.3^{12}\)
\(\Leftrightarrow3^{x+3}=9.3^{12}\)
\(\Leftrightarrow3^{x+3}=3^{14}\)
\(\Leftrightarrow x+3=14\Leftrightarrow x=11\)
\(\Leftrightarrow2\cdot3^{x+3}=3^{12}\cdot18\\ \Leftrightarrow2\cdot3^{x+3}=3^{14}\cdot2\\ \Leftrightarrow x+3=14\Leftrightarrow x=11\)
2.3x+3=10.312+8.3122.3x+3=10.312+8.312
=2.3x+3=18.312⇔2.3x+3=18.312
=3x+3=9.312⇔3x+3=9.312
=3x+3=314⇔3x+3=314
=x+3=14⇔x=11
2.3x + 5.3x + 1 = 153
\(2.3^x+5.3^x.3=153\Leftrightarrow2.3^x+15.3^x=153\)
\(\Leftrightarrow17.3^x=153\Leftrightarrow3^x=9\Leftrightarrow x=2\)
\(\Leftrightarrow2.3^x+5.3.3^x=153\)
\(\Leftrightarrow17.3^x=3^2.17\)
\(\Leftrightarrow3^x=3^2\Rightarrow x=2\)
812 nhận 5 công 812 nhân 7 trừ 7 trừ 812 nhận 2 tính bằng cách thuận tien nhất
25 nhân 5 nhân 4 nhân 3 tính bằng cách thuận tiện nhất
812 x 5 + 812 x 7 - 7 - 812 x 2 ???
toàn câu hỏi sai
2.3x=10.312+8.274
mình thêm nhé
2.3x=10.312+8.274
2.3x=10.312+23.312
2.3x=312.18
2.3x=312.32.2
2.3x=314.2
=>x=14
4.3x+2 − 2.3x+1 = 810
Ta có: \(4.3^{x+2}-2.3^{x+1}=810\)
\(4.3^{x+1}.3-2.3^{x+1}=810\)
\(2.3^{x+1}\left(2.3-1\right)=810\)
\(2.3^{x+1}.5=810\)
\(3^{x+1}=81=3^4\)
x+1=4
x=3
Tính: a) (231 - 39) - 231 b) ( -212) -( 57 - 212) c) 721 - ( 721- 12) d) (-812 - 45) - ( 55 - 812)