Respuesta :

[tex]x^2 - 18x + ( \frac{18}{2})^2 =29 + ( \frac{18}{2})^2[/tex]

[tex]x^2 - 18x + (9)^2 =29 + (9)^2[/tex]

[tex](x - 9)^2 = 119[/tex]

The number to add is 9² which is 81.

Answer: 81

Answer:  The required number to be added is 81.

Step-by-step explanation:  We are given to find the number that must be added to both sides of the equation below to complete the square.

[tex]x^2-18x=29~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)[/tex]

Completing the square means adding a suitable number to an expression such that is becomes a perfect square trinomial.

We have from equation (i) that

[tex]x^2-18x=29\\\\\Rightarrow x^2-\times x\times9=29\\\\\Rightarrow x^2-2\times x\times 9+9^2=29+9^2\\\\\Rightarrow (x+9)^2=29+81\\\\\Rightarrow (x+9)^2=110.[/tex]

Thus, the required number to be added is 81.