SVP c'est important aider moi

a) √63 = 3√7
b ) √175 = 5√7
c) 9√7 - 2√28 = 9√7 -4√7= 5√7
d) √24+√54  = 2√6+3√6 = 5√6
e) 3√50-√98 -√18 = 15√2-7√2-3√2 = 5√2
f) 3√20 +4√45 -√125 = 6√5+12√5-5√5 = 13√5