1) A = 9x² + 12x + 4
A = (3x + 2 )²
B = 4x² - 20x + 25
B = ( 2x - 5)²
C = 16x² - 49
C = ( 4x - 7 )( 4x + 7)
2) (x + 4) (5x + 2) = 0
Donc :
a) x + 4 = 0
alors x = -4
b) ou 5x + 2 = 0
alors 5x = -2
x = -2/5
3) E = [tex] \frac{7}{2} ( \frac{1}{4} + \frac{2}{5} )
[/tex]
= [tex] \frac{7}{2} ( \frac{5+8}{20} ) [/tex]
= [tex] \frac{7}{2} ( \frac{13}{20} ) [/tex]
= [tex] \frac{7×13}{2×20} [/tex]
E = [tex] \frac{91}{40} [/tex]
