Represent the following as one rational number 5/14 + 1/6 - (-13 4/5)
A: 6.4
B: 22
C: 28
D: -21

Step-by-step explanation:

Given this quadratic expression.

x² – 10x + c = 0

We are to find the value c that will make the expression a perfect square'

Using the completing the square method

Add the square of the half of coefficient of x

Coefficient of x = -10

Half of -10 = 1/2(-10) = -5

Square of -5 = (-5)^2 = 25

Hence the value of c to complete the expression is 25