Question

If (p+q) = 25 and p^2 +q^2= 225 then find the value of pq
Step by step explanation

Answer 1

Answer:

Step-by-step explanation:

To find the value of pq

Step = (p + q)[L.H.S] = 25(R.H.S)[Given]

              $p^{2}$ + $q^{2}$ = 225[GIVEN]

Make both the L.H.S and R.H.S of (p + q) = 25 whole raised to power 2 so that we could find the value of pq easily

That is,

$(p + q)^{2}$ = $25^{2}$

$p^{2}$ + 2pq + $q^{2}$[Using identity $(a + b)^{2}$ =  $a^{2}$ + 2ab + $b^{2}$] = 625

$p^{2}$ + $q^{2}$ + 2pq = 625

As  $p^{2}$ + $q^{2}$ = 225[Given]

225 + 2pq = 625

Follow the rules of linear equation

2pq = 625 - 225

2pq = 400

pq = 400/2

     = 200