Question

write f(x) = x2 - 3x -7 in completed square​

Answer 1

Solve by Completing the Square x^2+3x-7

x2+3x−7=0x2+3x-7=0

Add 77 to both sides of the equation.

x2+3x=7x2+3x=7

To create a trinomial square on the left side of the equation, find a value that is equal to the square of half of bb.

(b2)2=(32)2(b2)2=(32)2

Add the term to each side of the equation.

x2+3x+(32)2=7+(32)2x2+3x+(32)2=7+(32)2

Simplify the equation.

x2+3x+94=374x2+3x+94=374

Factor the perfect trinomial square into (x+32)2(x+32)2.

(x+32)2=374(x+32)2=374

Solve the equation for xx.

x=±√372−32x=±372-32

The result can be shown in multiple forms.

Exact Form:

x=±√372−32x=±372-32

Decimal Form:

x=1.54138126…,−4.54138126…x=1.54138126…,-4.54138126…