Solve the Quadratic Equation: x² - 16 = x + 4 Step-by-Step

Question

Solve the following equation:

$x^2-16=x+4$

00:00 Find X

00:03 Use the shortened multiplication formulas

00:15 Break down 16 into 4 squared

00:21 Use the shortened multiplication formulas and build a trinomial

00:28 Divide by the common factor

00:41 Reduce what we can

00:47 Isolate X

00:55 And this is the solution to the question

Please note that the equation can be arranged differently:

x²-16 = x +4

x² - 4² = x +4

We will first factor a trinomial for the section on the left

(x-4)(x+4) = x+4

We will then divide everything by x+4

(x-4)(x+4) / x+4 = x+4 / x+4

x-4 = 1

x = 5