Sagot :
Bonjour,
A = - 3a (a-5) = 3a² + 15a
B= (-2b+4) (5b-3)
-10b² +6b +20b -12
-10b² +26b -12
F= - 2f+2*(-4f)+(-9f)*(f+4)-3f*7f
2f - 8f + ( -9f² -36f) -21f²
2f +8f -9f² -36f -21f²
-30f² -26f
Réponse :
A=-3a(a-5)
=-3a*a+3a*5
=-3a2 (au carré) +15a
B=(-2b+4)(5b-3)
=-2b*5b-2b*(-3)+4*5b-4*3
=-10b2+6b+20b-12
=10b2+26b-12
F=-2f+2*(-4f)+(-9f)*(f+4)-3f*7f
=-2f-8f-9f2-36f-21f2
=-30f2-46f