Bonjour !
A = 2(x+5) + x(x+5) = (x+5)(2+x)
B=9b-9 = 9b - 9*1 = 9(b-1)
C= 5t + 15 = 5t + 5*3 = 5(t+3)
D=5a2 - 4a = a * 5a - a*4 = a(5a - 4)
E = (2x-3)(x+5) + (4x-6)(2x+3)
= (2x-3)(x+5) + 2(2x-3)(2x+3)
= (2x-3)[ (x+5) + 2(2x+3) ]
= (2x-3)[ x+5 + 4x+6 ]
= (2x-3)(5x +11)
Voilà !