X squared minus 18x minus 144 equals 0. Solve by factoring.

Answer got deleted because I have to explain it better, which I will kindly do.

(x^2 - 18x - 144) = 0

What two factors add up to equal - 18 AND multiply to equal - 144?

For a product to be a negative, one of the factors have to be a positive, and the other has to be a negative (positive times a negative equals a negative).

And now that we know that, we know that the negative number has to be larger than the positive because of the - 18.

What two factors add up to equal - 18 AND multiply to equal - 144?

Negative 24 and positive 6.

(x - 24) (x + 6)

X^2 - 18x - 144 = 0

Factorise:



We choose 2 numbers that add to - 18, and multiply to 144, these numbers are +6 and - 24, we put it into the brackets:

(x + 6) (x - 24) < - x = the interted sign of the numbers inside the brackets

E. g. + 6 turns into - 6 and - 24 turns into + 24

x must = - 6 or = + 24