-4-(-10) = -4+10 = 6

-10-(-4) = -10+4= -6

Therefore, 6-(-6) = 6+6 = 12

The quadratic equation whose roots are reciprocal of 2 x 2 + 5 x + 3 = 0 can be obtained by replacing x by 1/x.

Hence, 2(1/x)(1/x)+ 5(1/x) + 3 = 0

=>  3 x 2 + 5 x + 2 = 0

Unit digit of this expression is always 1 as the base ends with 1. 

For the tenth place digit we need to multiply the digit in the tenth place of the base and unit digit of the power and take its unit digit.

i.e, tenth place digit in 2151 is 5 and

tenth place digit in power 415 is 1

And the units digit in the product of 5 x 1 = 5

Therefore, last two digits of  2151 415 is 51.

This can be done in a method called Approximation.

Now, 

$$\begin{gathered} 5 2 + 6 3 + 6 + 7 2 = ? x 3 . 34 \\ 25 + 216 + 6 + 49 = ? x 3 . 34 \\ 296 = ? x 3 . 34 \\ ? = 296 3 . 34 = 88 . 622 ? 89 \end{gathered}$$

$$\begin{gathered} 7 + 7 ÷ 7 + 7 x 7 + 7 - 7 ÷ 7 + 7 x 7 \\ = 7 + 1 + 49 + 7 - 1 + 49 \\ = 8 + 56 + 48 \\ = 56 + 56 \\ = 112 \end{gathered}$$

Using BODMAS law,

3 x 3 + 3 - 3 + 3 =

3 x 3 = 12

= 12 + 3 - 3 + 3

=  9 + 3

= 12

Hence, 3 x 3 + 3 - 3 + 3 = 12.

? = 5068 x 4/37

? = 548

Given 7 + 7/7 + 7 x 7 - 7

By using BODMAS rule,

7 + 1 + 7 x 7 - 7

= 8 + 49 - 7

= 57 - 7

= 50.

Hence 7 + 7/7 + 7 x 7 - 7 = 50.

Given equation is  

   19 2 . 5 × 19 p = 19 7   

Here it is in the form of  a m × a n = a m + n  

 Here m = 2.5 , n = p, m+n = 7

 => 2.5 + p = 7 

 => p = 7 - 2.5

 => p = 4.5

Here the given expression, 

X 2 + X 2 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  X 2

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

Therefore, 

X 2 + X 2 = 2 X 2.