Verbal Reasoning - Mental Ability Questions

Here the given expression, 

X2 + X2 is an algebraic expression. Here in this expression the terms are like terms. Now to add them, add their coefficients.

Here in the given expression, the like terms are two X2

Hence, adding their coefficients i.e, 1 + 1 = 2

Therefore, 

X2 + X2 = 2X2.

Here given formula is 

a2 + b2 + c2 -ab- bc - ca = 0

and it is possible if and only if a = b = c.

From the trial and error method, 

1) Let a = b = c = 1

Now substitute these values of a, b, c in the above formula.

We get 1 + 1 + 1 - 1 - 1 - 1 = 3 - 3 = 0

2) Now, let a = b = c = 4

Now substitute these values of a, b, c in the above formula.

We get 16 + 16 + 16 - 16 - 16 - 16 = 48 - 48 = 0.

Hence, it is possible that 

a2 + b2 + c2 -ab- bc - ca = 0 iff a = b = c.

 Clearly, (3rd column)² + (2nd column)² = (1st column)²
In the first row, 5² + 12² = 13².
In the second row, 8² + 15² = 17².
Let the missing number in the third row be y.
Then y² + 24² = 25² or y² + 576 = 625 or y² = 49 or y = 7.

A tangent contains ZERO chords, as it touches the circle at only one point.

Hence, it does not contain any chord.