Question

rezolvati in Recuatia 4xla putera 2-25=0

Answer 1

4x² - 25 = 0 
( 2x)² - 5² = 0 
( 2x -5) ·( 2x + 5) = 0 
2x- 5 = 0          ;    x = 5 /2 
2x + 5 = 0            x = - 5 /2 
S = { - 5 /2  ; 5 /2} 

Answer 2

$\displaystyle 4x^2-25=0 \\ a=4,b=0,c=-25 \\ \Delta=b^2-4ac=0^2-4 \cdot 4 \cdot (-25)=0+400=400\ \textgreater \ 0 \\ x_1= \frac{0+ \sqrt{400} }{2 \cdot 4} = \frac{0+20}{8} = \frac{20}{8}= \frac{5}{2} \\ \\ x_2= \frac{0- \sqrt{200} }{2 \cdot 4} = \frac{0-20}{8} = \frac{-20}{8} =- \frac{5}{2} \\ \\ S=\left\{- \frac{5}{2} ; \frac{5}{2} \right \}$