Mathematical problems: calculation: 2 √ 2 + 5 √ 2 = (), 3 √ 5 ×√ 5 = ()

Mathematical problems: calculation: 2 √ 2 + 5 √ 2 = (), 3 √ 5 ×√ 5 = ()

2√2+5√2=( 7√2),3√5×√5=(15 )