Bonsoir,
Développer et réduire f(x) :
f(x) = 36x² - 25( x-3 )²
f(x) = 36x² - 25 ( x²-6x+9 )
f(x) = 36x² - 25x² + 150x - 225
f(x) = 6x² + 150x - 225
Factoriser f(x)
f(x) = 36x² - 25( x-3 )²
f(x) = 6² x² - 5² ( x-3 )²
f(x) = ( 6x )² - [ 5( x-3 ) ] ²
f(x) = ( 6x )² - ( 5x-15 )²
f(x) = ( 6x+5x-15 ) ( 6x-5x+15 )
f(x) = ( 11x-15 ) ( x+15 )
