Question

if p+q =7 and pq = 12 find the value of p2 + q2

Answer 1

Explanation:

Given,

$\mathsf{p+q=7,\:pq=12}$

$\mathsf{(p+q)^2=7^2}$

$\mathsf{==>p^2+q^2+2pq=49}$ [∵ $\mathsf{(a+b)^2=a^2+2ab+b^2}$]

$\mathsf{==>p^2+q^2+2(12)=49}$

$\mathsf{==>p^2+q^2+24=49}$

$\mathsf{==>p^2+q^2=49-24}$

∴ $\mathsf{p^2+q^2=25}$

Answer: 25

I hope this helps. :D