Respostas

2013-05-01T19:14:48-03:00

a) 4-3x=14+2x

4 - 14 = 3x + 2x

5x = -10

x = -2

 

b) 2-3x/8-2x+3/2=x-1/4

2 - 3x - 8x + 12 = 2x - 2

2 + 12 + 2 = 2x + 3x + 8x

16 = 13x

x = 16/13

 

c) 5x²-9x-2=0

Delta = 81 - 4 * 5 * (-2) = 81 + 40 = 121

x = [- (-9) +/- raiz quadrada de 121] / 2*5

x = (9 + 11)/10 = 20/10 = 2

x = (9-11)/10 =  -2/10 = -1/5

 

d) x²-3x-2= x+10

 x² - 3x - 2 - x - 10 = 0 x² - 4x - 12 = 0 S = 4  P = -12 x = 6 ou x = -2