What is the missing constant term in the perfect square that starts with ${\mathrm{x}}^2+10\mathrm{x}+\mathrm{c}= 0$?

Given equation: ${\mathrm{x}}^2+10\mathrm{x}+\mathrm{c}= 0$

General equation is ${\mathrm{x}}^2+2\mathrm{bx}+\mathrm{c}=0$ .........(1)

Here, 2b = 10

b = 5

Upon completing the square method by algebraic identity,

$(a+b{)}^2=a^2+2ab+b^2$         .........(2)

By comparing equation (1) and equation (2), we get

$\mathrm{c} = {\mathrm{b}}^2$

Hence value of $\mathrm{c} = {\mathrm{b}}^2=25$