Question

If p+q=9 and pq=36,find
i)p2-q2​

Answer 1

(p-q)2=p2-q2+2pq

(9)2=p2-q2+2*36

81=p2-q2+72

81-72=p2-q2

9=p2-q2

This the answer for the given question

Answer 2

Hi there !!

P - Q = 9

PQ = 36

To find :- p² - q²

---> To form Equations

Squaring both sides,

(p-q)² = 9²

p²+ q² - 2pq =81

p²+ q² - 2(36)= 81 (given )

p²+ q²- 72=81

p²+ q² = 153

Now, Considering second equation

(p+q)²

p²+ q² + 2pq = 153

p²+ q² = 225

p+ q = 15

Now, 1)Ist part

p²- q² = ?

(p+q)(p-q) ( Identity)

= 9 × 15 = 135

Thank you :)