Question

What value for C will make the expression a perfect square trinomial x2-7x+c

Answer 1

49/4

Explanation:

To make x2-7x+c a perfect square trinomial we do it by completing the square method. First, make half of the coefficient of x then add and subtract by squaring it. c=49/4 this is the required value of c.

Answer 2

The value of c is 12.25

Explanation:

we know that

A perfect square trinomial is of the form

`(x-a)^(2)=x^(2)-2ax+a^(2)`

In this problem we have

`x^(2)-7x+c`

so

equate the equations

`x^(2)-7x+c=x^(2)-2ax+a^(2)`

we have

the following equations

`-7x=-2ax` -----> equation A

and

`c=a^(2)` -----> equation B

Solve the equation A

`-7x=-2ax`

`7=2a`

`a=3.5`

Solve the equation B

`c=a^(2)`

`c=3.5^(2)=12.25`

therefore

`(x-3.5)^(2)=x^(2)-7x+12.25`

The value of c is 12.25