Répondre :
tu remplace x par (-2/3)
(4x-3)²= ( (4*(-2/3)- 9/3)
=(-8/3)-9/3)
=(-17/3)²
=289/9
(2x+7)= 2(-2/3)+7
=-4/3 +7
-28/21 + 21/21
=-8/21
(4x-3)=
(4(-2/3)-9/3)
= -8/3 -9/3
=-17/3
(2x+7)(4x-3)=-8/21 x -17/3
= 136/63
f(-2/3) =(289/9)+(163/63)
(63/63)(289/9)+(9/9)(163/63)
=(18207/567)+(1467/567)
=19674/567
= environ 34,7