Solve for X: 3x+7+3x+5-x = 3(x-3)(x+3)+5x Linear-Quadratic Equation

Question

Solve the following equation:

3x+7+3x+5x=3(x3)(x+3)+5x 3x+7+3x+5-x=3(x-3)(x+3)+5x

Video Solution

Solution Steps

00:00 Solve
00:03 Collect terms
00:23 Use abbreviated multiplication formulas
00:40 Reduce what's possible
00:47 Divide by 3
01:02 Arrange the exercise so that 0 is on one side of the equation
01:15 Break down 13 into square root of 13 squared
01:18 Again use abbreviated multiplication formulas to find solutions
01:26 Find the two possible solutions
01:41 And this is the solution to the question

Step-by-Step Solution

To solve this problem, let's follow these steps:

  • Step 1: Simplify the left-hand side of the equation:
    Combine like terms: 3x+3xx+7+5=5x+123x + 3x - x + 7 + 5 = 5x + 12.
  • Step 2: Expand and simplify the right-hand side:
    Apply the difference of squares: 3(x3)(x+3)=3(x29)3(x-3)(x+3) = 3(x^2 - 9).
    This simplifies to 3x2273x^2 - 27.
    Then add 5x5x: 3x227+5x3x^2 - 27 + 5x.
  • Step 3: Equate both sides and solve for xx:
    We have 5x+12=3x2+5x275x + 12 = 3x^2 + 5x - 27.
    Subtract 5x5x and 12 from both sides: 0=3x2390 = 3x^2 - 39.
    This simplifies to 3x2=393x^2 = 39.
    Divide by 3: x2=13x^2 = 13.
    Taking the square root of both sides, we find x=±13x = \pm\sqrt{13}.

Therefore, the solution to the equation is x=±13 x = \pm\sqrt{13} .

Answer

±13 ±\sqrt{13}