Verified answer

Réponse :

N°49:

A= -3X(2X+3)

= -6 X² -9 x

B= - 7X(3-5X)

= -21X²+35X²

= 14X²

C=X+3X(X+10)

=X+3X²+30X

=3X²+31X

D= -2(-X-4)+12

=+2X+8+12

=2X + 20

E=X²-2(X-3X²)

=x² - 2X +6X²

=7X²-2X

F=(4t-1) x (-t) + t

= -4t²+t+t

= -4t²+2t

N°51:

E= -5(8X-3)+9-2X+6(7X-4)

= - 40X + 15 + 9 - 2X + 42X -24    

= -42X + 42X +24 - 24

=0

Pour X = - 1 542,7

E= -5(8X-3)+9-2X+6(7X-4)

= -5 [ 8(- 1 542,7)-3+9-2(- 1 542,7)+6[7(- 1 542,7) - 4 ]

=-5 ( - 12341,6)-3+9+3085,4+6(-10798,9)-4

=+61708-3+9+3085,4-64793,4-4

=64802,4 - 64800,4

=2

N°52

1. n(n+10) - n²

n²+10n-n²

= 10n

2. Je ne sais pas !