Thread: problem with sequence and means

the A.S mean of two no.s : 8,2x^2 exceeds their positive G.M by 9 .Find X
i got it 5, -5 is that right?

Originally Posted by mido22

the A.S mean of two no.s : 8,2x^2 exceeds their positive G.M by 9 .Find X
i got it 5, -5 is that right?

(8+2x^2)/2 -9 = root (16x^2) So4+x^2 -9 =4x So x^2-4x-5=0 (x-5)(x+1)=0 So x=5 (cant be -1 in this question)
If x=5 2x^2= 50 So the two numbers are 8 and 50 (which you can check are correct)

but -5 is also correct

Yes, mido22, x= 5 and x= -5 are the answers.