URGGEEENNT BONSOIR J'ai ce devoir a faire pour demain MERCI DAVANCE

A=19x99+19
=1881+19
=1900

B=(101x101)-101
=10201-101
=10100

A = 19 x 99 + 19
A = 1.881 + 19
A = 20.881

B = 101² - 101
B = 10.201 - 101
B = 10.201

C = 2.5² + 2 x 2.5 x 7.5 + 7.5²
C = 2.5² + 5 x 7.5 + 7.5²
C = 2.5² + 37.5 + 7.5²
C = 6.25 + 37.5 + 56.25
C = 43.75 + 56.25
C = 100