Solve (x+3)² = (x-3)²: Finding Values When Squared Binomials Are Equal

Question

(x+3)2=(x3)2 (x+3)^2=(x-3)^2

Video Solution

Solution Steps

00:06 Let's find the value of X.
00:09 Use the short multiplication formulas to open all brackets. Ready? Here we go!
00:22 Now, solve the multiplications and calculate the squares. You're doing great!
00:33 Next, simplify everything we're able to. Keep it up!
00:46 Now, isolate X on one side of the equation.
00:55 And that's how we find the solution to the problem! Well done!

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 this formula and expand the parentheses in the expressions in the equation:

(x+3)2=(x3)2x2+2x3+32=x22x3+32x2+6x+9=x26x+9 (x+3)^2=(x-3)^2 \\ x^2+2\cdot x\cdot3+3^2=x^2-2\cdot x\cdot3+3^2 \\ x^2+6x+9=x^2-6x+9 \\ 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+6x+9=x26x+912x=0/:12x=0 x^2+6x+9=x^2-6x+9 \\ 12x=0\hspace{8pt}\text{/}:12\\ \boxed{x=0} Therefore, the correct answer is answer A.

Answer

x=0 x=0