Question

if a+2b=5 and ab=2 find a^2+4b^2​

Answer 1

Step-by-step explanation:

➡Given here.

↪a+2b = 5...........(1).

↪ab= 2..................(2).

➡Find here .

↪a²+4b²= ?.

➡Now,we know

♠(x+y)²= x²+2xy+y².

➡So,

▶(a+2b)²= a²+4ab +4b².

[ keep value by (2). and (1).]

♠(5)²=a²+4b²+4×2.

=> a²+4b²= 25-8.

=>a²+4b²= 17.

➡Hopes its helps u.

Answer 2

Answer:

Answer is 17

Step-by-step explanation:

we have

          >> a+2b=5   .............(1)

         >> ab=2    >> a=2/b     ........(2)

          >>a^2+4b^2             ..........(3)

       putting (2) in (1) we got,

        2/b+2b=5

        2+2b^2-5b=0

 by factorization we got,

       b=1/2  , 2

put the values in (2) , we got

             >> a=4    when b=1/2,

           >> a=1       when b=2,

therefore putting values of a & b simultaneously  in eq'n (3) we got

    >>  when a=4    , b=1/2

           (4)^2+4 x (1/2)^2 =  16+1=>>17

  >> when  a=1    ,b=2

           (1)^2+4(2)^2  =  1+16 =>>17

I hope it helps.