Tìm x

a) 210 - 5x =
c) 210 - 5(x-11)
= 200;
e) 450: [41- (2x - 5)] = 3².5;
200;
b) 210: x-10 = 20;
d) (2x + 1): 7 = 2² + 3²;
E
f) (5x-9) 7+3= 80.