1) x² - 49 =0
x² = 49
x = √49
x1=7............x2= - 7
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2) (x+5)/10 = (2x-3)/(12-x)
(x +5) (12-x) = (2x - 3)(10)
12x - x² + 60- 5x = 20x - 30
12x - x² + 60 - 5x - 20x + 30 = 0
- x² - 13x + 90 = 0
x1 = - 5............x2= 18
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3)14x² -13x-12=0
x1 = 1,53.............x2=-0,60
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4)x² - 2[3x-6+x-2] =0
x² - 6x + 12 -2x + 4 = 0
x² - 8x + 16 = 0
x1=4.............x2=4
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5)2x² -19x =10
2x² - 19x - 10 = 0
x1= 10.................x2= -1/2
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6) 4x² +2x-1=10(x+1)
4x² + 2x - 1 - 10x - 1= 0
4x² - 8x - 2 = 0
x1 =2,22........x2= - 0,22
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7) x² = (2-x)/6
6x² = 2 -x
6x² - 2 + x = 0
6x² + x - 2 = 0Â
x1= 1/2.............x2=-2/3
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8) 2u² - u - 3= 0
u1= 1,5..........u2 =- 1
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espero que te sirva, salu2!!!