aidez moi urgeeent svpppppppppppppppp

Bonjour

a = 5/7 - 1/7 x ( 10/2 + 1/2)
a = 5/7 - 1/7 x 11/2
a = 5/ 7 - 11 /14
a = 10/14 - 11/14 = - 1/14

b = 105 x 10⁴ sur 5 x 10 ²
b = 21 x 10 ² = 2.1 x 10 ³

c ) √75 = 5√3 

d = ( 2√5) ² - 3 + 6 √75
d = 20 - 3 + 30√3
d = 17 + 30√3