Question

18.Rezolvati următoarele ecuatii b)3(x+5)-(2x-1)la a doua -13=5(1-x)(1+x)+(x-3) la a doua. c)(2x-3)(2x+3)-4x(x+1)=2(x+3)+3 va rog frumos

Answer 1

b) 3(x+5) - (2x-1)² = 5(1-x)(1+x) + (x-3)²
3x + 15 - ( 4x² - 4x + 1 ) = 5( 1 - x² ) + x² - 6x + 9
3x + 15 - 4x² + 4x - 1 = 5 - 5x² + x² - 6x + 9
7x + 14 - 4x² = 14 - 4x² - 6x
7x = -6x
7x + 6x = 0 
13x = 0 ⇒ x = 0 


c) (2x-3)(2x+3) - 4x(x+1) = 2(x+3) + 3
4x² - 9 - 4x² - 4x = 2x + 6 + 3
-9 - 4x = 2x + 9
-4x - 2x = 9 + 9 
-6x = 18 ⇒ x = - 3

Answer 2

ai rezolvarea.........