Question

a平方—4b-4=0,a平方+2b平方=3,则2分之一a平方b+2b的值是多少?

Answer 1

a^2-4b-4=0

a^2+2b^2=3

二式相减得到:2b^2+4b=-1

b^2+2b=-1/2

(b+1)^2=1/2

b+1=(+/-)根号2/2

b=-1(+/-)根号2/2

a^2=3-2b^2=3-2(-1(+/-)根号2/2)=5(-/+)根号2

a^2b/2+2b

=b(5/2(-/+)根号2/2+2)

=(-1(+/-)根号2/2)*(9/2(-/+)根号2/2)

=...