Solve the Quadratic Equation: 3x² + 7 = 2x² + 9

Question

Solve the following exercise

x3x+7=2x2+9 x\cdot3\cdot x+7=2x^2+9

Video Solution

Solution Steps

00:00 Find X
00:03 Calculate the products
00:09 Isolate X
00:35 Extract the root
00:39 When extracting a root there are always 2 solutions (positive, negative)
00:42 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Simplify the given expression.
  • Rearrange into standard quadratic form.
  • Solve using applicable method.

Let's begin the process:
1. Simplify the left-hand side: x3x+7=3x2+7 x \cdot 3 \cdot x + 7 = 3x^2 + 7 .

2. Set up the equation by balancing: 3x2+7=2x2+9 3x^2 + 7 = 2x^2 + 9 .

3. Rearrange the terms to form a quadratic equation: 3x22x2+79=0 3x^2 - 2x^2 + 7 - 9 = 0 .

This simplifies to: x22=0 x^2 - 2 = 0 .

4. Solve for x x :
By adding 2 to both sides, we have: x2=2 x^2 = 2 .
Take the square root of both sides: x=±2 x = \pm\sqrt{2} .

Therefore, the solution to the problem is ±2 \pm\sqrt{2} .

Answer

±2 ±\sqrt{2}