Solve the Equation: Finding x in (x+1)² = x² + 13

Question

(x+1)2=x2+13 (x+1)^2=x^2+13

Video Solution

Solution Steps

00:00 Find X
00:03 Use shortened multiplication formulas to expand the brackets
00:09 Solve the multiplications and squares
00:16 Simplify what we can
00:20 Isolate X
00:38 And this is the solution to the problem

Step-by-Step Solution

Let's solve the equation. First, we'll simplify the algebraic expressions using the perfect square binomial formula:

(a±b)2=a2±2ab+b2 (a\pm b)^2=a^2\pm2ab+b^2 We'll apply the mentioned formula and expand the parentheses in the expressions in the equation:

(x+1)2=x2+13x2+2x1+12=x2+13x2+2x+1=x2+13 (x+1)^2=x^2+13 \\ x^2+2\cdot x\cdot1+1^2=x^2+13 \\ x^2+2x+1=x^2+13

We'll continue and combine like terms, by moving terms between sides. Then we can notice that the squared term cancels out, therefore it's a first-degree equation, which we'll solve by isolating the variable term on one side and dividing both sides of the equation by its coefficient:

x2+2x+1=x2+132x=12/:2x=6 x^2+2x+1=x^2+13 \\ 2x=12\hspace{8pt}\text{/}:2\\ \boxed{x=6} Therefore, the correct answer is answer B.

Answer

x=6 x=6