If x - y = -9 and xy = -20, then find $x^2 + y^2$
1). 61
2). 41
3). 85
4). 113
6. .If a + b = 10 and ab = 21, then the value of $(a-b)^{2}$ is
7. What value should come in the place of question mark (?) in the following questions ?
8. What is the value of (2.3 + 1.7)2 – (2.3 – 1.7)2?
9. O is the incentre of $\triangle ABC$ and $\angle A$ = $30^{0}$, then $\angle BOC$ is