kazah
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2 éve
1,
a,
`(x+4)(x-4)=x^2-2x` (zárójelbontás)
`x^2-16=x^2-2x` (`-x^2`)
-16 = -2x (:-2)
x = 8
b,
100x-100(27-x) = 1100 (z.b.)
100x-2700+100x = 1100 (összevonás)
200x-2700 = 1100 (+2700)
200x = 3800 (:200)
x = 19
c,
`(x+3)/12-(5-x)/12=2/3` (*12)
(x+3)-(5-x)=8 (z.b,)
x+3-5+x = 8 (ö.v.)
2x-2 = 8 (+2)
2x = 10 (:2)
x = 5
2,
a,
`(5x)/4-(2-7x)/5=3x-13` (*20)
25x-(8-28x) = 60x-260 (z.b.)
25x-8+28x = 60x-260 (ö.v.)
53x-8 = 60x-260 (-53x)
-8 = 7x-260 (+260)
7x = 252 (:7)
x = 36
b,
`(2x-3)^2-(2x-5)^2=40` (z.b.)
`4x^2-12x+9-4x^2+20x-25=40` (ö.v.)
8x-16 = 40 (+16)
8x = 56 (:8)
x = 7
c,
`3+(4x-5)/5-(5x-4)/15=(15-3x)/10` (*30)
90+(24x-30)-(10x-8)=45-9x (ö.v.)
68+14x = 45-9x (+9x)
68+23x = 45 (-68)
23x = -23 (:23)
x = -1
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