Question

（a^2+3a+2分之a^2+3a）÷（a+1分之a+3）-（a+2分之2）,其中a=根号2,先化简后求值

Answer 1

（a^2+3a+2分之a^2+3a）÷（a+1分之a+3）-（a+2分之2）,

=[a(a+3)/(a+1)(a+2)]÷[(a+3)/(a+1)]-2/(a+2)

=a/(a+2)-2/(a+2)

=(a-2)/(a+2)

当a=√2时,原式=(√2-2)/(√2+2)=(2+4-4√2)/(2-4)=2√2-3