Question

determinati cifra x solutie a ecuatiei : (cu bara deasupra )
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0.2(x+1) + 0,(x+1 )1 + 0,xx = 0,3(x-2) + 1,09

Answer 1

Răspuns:

(0.2x+0.2)+(0.x+1)+0.xx=0.3x-0.6+1.09

0.2x+0.x^2+1.2=0.3x+0.50

0.2x+0.x^2+1.2-0.3x+0.5=0

0.x^2-0.1x+1.7=0|*10

a=0.1

b=-0.1

c=1.7

Delta= b^2-4ac

Delta=0.01-4*-0.1*1.7

Delta=0.01+0.4*1.7

Delta=0.01+0.7=0.71

x12=-b+√b^2-4ac/2a

x12=0.1+√0.71/0.2

x12=0.8/0.2=0.4