Aidez moi svp merci f(x) = (2x-1)(x+5)-3(2x-1) x = racine carré de 2

Bonsoir

(2x -1)(x +5 )- 3(2x -1)
pour x = √2

( 2 √2 - 1) ( √2 + 5) - 3( 2√2 - 1)
= 2 √4 + 10√2 - √2 - 5 - 6√2 + 3
= 4√2 - 10√2 - √2 - 5 - 6√2 +3
= - 13√2  -2 

f(√2)= (2√2-1)(√2+5)-3(2√2-1)
f(√2)= 2√2*√2+5*2√2-1*√2-1*5-6√2+3
f(√2)= 4+10√2-√2-5-6√2+3
f(√2)= 3√2+2