Question

If p+q=7 and pq=1 ,find the value of p-q​

Answer 1

Answer:

The answer is $p-q=3\sqrt 5$

Step-by-step explanation:

Since we know that

$(p-q)^2=p^2+q^2-2pq=(p+q)^2-4pq$, using $(a+b)^2=a^2+b^2+2ab$

$\Rightarrow (p-q)^2=(7)^2-4(1)=49-4=45\\\therefore p-q=\sqrt{45}=\sqrt{9\times 5}=\sqrt 9\times \sqrt 5=3\sqrt 5$