1.tìm X€N biết:
a.33x-1+2×34=5×34.
b.(2x-1)=25.
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a: 3x=81
nên x=27
b: \(5\cdot4^x=80\)
\(\Leftrightarrow4^x=16\)
hay x=2
c: \(2^x=4^5:4^3\)
\(\Leftrightarrow2^x=2^4\)
hay x=4
a)-2x - 3.(x - 17) = 34 - (-x + 25)
- 2x - 3x + 51 = 34 + x - 25
- 2x - 3x - x = -51 + 34 - 25
- 6x = - 42
x = 7
Vậy x = 7
b)-2x-3.(x-17)=34-2(-x+25)
- 2x - 3x + 51 = 34 + 2x - 50
- 2x - 3x - 2x = - 51 + 34 - 50
7x = - 67
x = \(-\frac{67}{7}\)
Vậy \(x=-\frac{67}{7}\)
c)17x-(-16x-37)=2x +43
17x + 16x + 37 = 2x + 43
17x + 16x - 2x = -37 + 43
31x = 6
x = \(\frac{6}{31}\)
Vậy \(x=\frac{6}{31}\)
=>(2x+3).(10x+2)=(5x+2).(4x+5)
=>(2x.10x)+(2x.2)+(3.10x)+(3.2)=(5x.4x)+(5x.5)+(2.4x)+(2.5)
=>20x2+4x+30x+6=20x2+25x+8x+10
=>20x2-20x2+4x-8x+30x-25x=10-6
=>0+4x-8x+30x-25x=4
=>-4x+30x-25x=4
=>26x-25x=4
=>x=4
B)=>(3x-1).(5x-34)=(40-5x).(25-3x)
=>15x2-102x-5x+34=1000-120x-125x+15x2
=>15x2-107x+34=1000-245x+15x2
=>15x2-15x2-107x+245x=1000-34
=>0-107x+245x=966
=>138x=966
=>x=7
A,=>(2x+3).(10x+2)=(5x+2).(4x+5)
=>(2x.10x)+(2x.2)+(3.10x)+(3.2)=(5x.4x)+(5x.5)+(2.4x)+(2.5)
=>20x2+4x+30x+6=20x2+25x+8x+10
=>20x2-20x2+4x-8x+30x-25x=10-6
=>0+4x-8x+30x-25x=4
=>-4x+30x-25x=4
=>26x-25x=4
=>x=4
B3 a) x=4 b) x=-7 c) x=5 d) x=4
B2 a) -3+ -2+ -1+0+1+2+3+4=4
b) -6+ -5+ -4+ -3+ -2+ -1+0+1+2+3+4=-11
c) -18+-17+-16+-15+-14+-13+-12+-11+-10+-9+-8+-7+-6+-5+-4+3+-2+-1+0+1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19=19
\(3^{3x-1}+2\cdot3^4-5\cdot3^4=0\)
\(\Leftrightarrow3^{3x-1}-3\cdot3^4=0\)
\(\Leftrightarrow3^{3x-1}-3^5=0\)
\(\Leftrightarrow3x-1=5\Leftrightarrow x=2\)
2x-1=25
2x=25+1
2x=26
x=26/2=13