tìm stn x :
a,2x + 3x = 1505
b,5x - x = 4088
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a)\(2x+3x=1505\)
=>\(x\left(2+3\right)=1505\)
=>x.5=1505
=>x=1505:5
=>x=301
b)\(5x-x=4088\)
=>x(5-1)=4088
=>x.4=4088
=>x=4088:4
=>x=1022
a) 2x + 3x = 1505
(2 + 3)x = 1505
5x = 1505
x = 1505 : 5
x = 301
b) 5x - x = 4088
5x - 1x = 4088
(5 - 1)x = 4088
4x = 4088
x = 4088 : 4
x = 1022
a ) \(2x+3x=1505=x\left(2+3\right)=1505=>5x=1505\)
\(=>x=301\)
b ) \(5x-x=4088=>x\left(5-1\right)=4088\)
\(=>4x=4088=>x=1022\)
a) 2x + 3x = 1505
x ( 2 + 3 ) = 1505
x . 5 = 1505
x = 1505 : 5
x = 301
b) 5x - x = 4088
5x - 1x = 4088
( 5 - 1 ) x = 4088
4x = 4088
x = 4088 : 4
x = 1022
\(a,2x+15=27\)
\(\Rightarrow2x=27-15\)
\(\Rightarrow2x=12\)
\(\Rightarrow x=12\div2\)
\(\Rightarrow x=6\)
1: =>\(5^{x-2}-9=2^4-\left(6^2-6^2\right)\)
=>\(5^{x-2}=16+9=25\)
=>x-2=2
=>x=4
2: \(\Leftrightarrow3^x+16=19^6:19^5-3=19-3=16\)
=>3^x=0
=>x=0
3: \(\Leftrightarrow2^x+2^x\cdot16=272\)
=>2^x*17=272
=>2^x=16
=>x=4
4: \(\Leftrightarrow2^{x-1}+3=24-\left(4^2-2^2+1\right)=24-\left(16-4+1\right)\)
=>\(2^{x-1}+3=24-16+4-1=8+4-1=12-1=11\)
=>2^x-1=8
=>x-1=3
=>x=4
Lời giải:
1. $(x+2)-2=0$
$x+2=2$
$x=0$
2.
$(x+3)+1=7$
$x+3=7-1=6$
$x=6-3=3$
3.
$(3x-4)+4=12$
$3x-4+4=12$
$3x=12$
$x=12:3=4$
4.
$(5x+4)-1=13$
$5x+4=13+1=14$
$5x=14-4=10$
$x=10:5=2$
5.
$(4x-8)-3=5$
$4x-8=5+3=8$
$4x=8+8=16$
$x=16:4=4$
6.
$3+(x-5)=7$
$x-5=7-3=4$
$x=4+5=9$
7.
$8-(2x-4)=2$
$2x-4=8-2=6$
$2x=6+4=10$
$x=10:2=5$
8.
$7+(5x+2)=14$
$5x+2=14-7=7$
$5x=7-2=5$
$x=5:5=1$
9.
$5-(3x-11)=1$
$3x-11=5-1=4$
$3x=11+4=15$
$x=15:3=5$
10.
$16-(8x+2)=6$
$8x+2=16-6=10$
$8x=10-2=8$
$x=8:8=1$
5x - x = 4088
( 5 - 1 ) x = 4088
4x = 4088
x = 4088 : 4
x = 1022
$ a/ 12x(x – 5) – 3x(4x - 10) = 120$
`<=>12x^2-60x-12x^2+30x=120`
`<=>-30x=120`
`<=>x=-4`
Vậy `x=-4`
$b/ 9x(x + 4) – 5x(3x + 2) = 112 - 2x(3x + 1)$
`<=>9x^2+36x-15x^2-10x=112-6x^2-2x`
`<=>-6x^2+26x=112-6x^2-2x`
`<=>28x=112`
`<=>x=4`
Vậy `x=4`
$c/ 3x(1 – x) - 5x(3x + 7) = 154 + 9x(5 – 2x)$
`<=>3x-3x^2-15x^2-35x=154+45x-18x^2`
`<=>-32x-18x^2=154+45x-18x^2`
`<=>77x=-154`
`<=>x=-2`
Vậy `x=-2`
a/ 2x + 3x = 1505
\(\Rightarrow\)5x = 1505
\(\Rightarrow\)x = 1505 : 5 = 301
Vậy x = 301
b/ 5x - x = 4088
\(\Rightarrow\)4x = 4088
\(\Rightarrow\)x = 4088 : 4 = 1022
Vậy x = 1022
a) 2x + 3x = 1505
=> 5x = 1505
x = 1505 : 5
x = 301
b) 5x - x = 4088
=> 4x = 4088
x = 4088 : 4
x = 1022