How do you solve 2x ^ { 2} - 13x + 18- ( x - 2) ^ { 2}?

1 Answer
Aug 7, 2017

(x-2)(x-7)

If we presume that the equation equals zero, then:

x=2 or x=7

Explanation:

2x^2-13x+18-(x-2)^2

We first expand the term (x-2)^2.

2x^2-13x+18-[x(x-2)-2(x-2)]

2x^2-13x+18-[x^2-2x-2x+4]

2x^2-13x+18-[x^2-4x+4]

We now open the brackets, changing the signs appropriately.

2x^2-13x+18-x^2+4x-4

Group all like terms with their preceding signs and then simplify.

2x^2-x^2-13x+4x+18-4

x^2-9x+14

Factorise.

x^2-7x-2x+14

x(x-7)-2(x-7)

(x-2)(x-7)

If we presume that the equation equals zero, then:

x-2=0 and x-7=0

x=2 or x=7