Answer: +5
Explanation:
Let the unknown number be x
The square of the unknown is x2
Therefore;
X2 - 10 = 3times of x
X2-10=3x
Collect like terms,so we have
X2-3x-10=0
Let's factorise
Values of -10 could be +2 and -5 or -2 and +5
But for us to get -3,we will use +2 &-5
X2+2x-5x-10=0
X(x+2)-5(x+2)=0
(X-5)(X+2)=0
X-5=0; X=+5
X+2=0;X=-2
Therefore, positive solution is +5