Solve the Quadratic Equation: Find X in (3x+1)^2 + 8 = 12

Question

Find X

(3x+1)2+8=12 (3x+1)^2+8=12

Video Solution

Solution Steps

00:00 Find X
00:03 Open brackets properly according to quadratic formula
00:13 Calculate squares and multiplications
00:24 Arrange the equation so the right side equals 0
00:31 Reduce as much as possible
00:37 Examine the coefficients
00:41 Use the root formula to find possible solutions
00:50 Substitute appropriate values and solve for solutions
01:07 Calculate the square and multiplications
01:18 Calculate square root of 16
01:23 These are the 2 options (positive and negative)
01:33 And this is the solution to the question

Step-by-Step Solution

To solve the equation (3x+1)2+8=12(3x + 1)^2 + 8 = 12, we start by isolating the squared expression:

  • First, subtract 8 from both sides to simplify: (3x+1)2=128(3x + 1)^2 = 12 - 8.
  • This gives (3x+1)2=4(3x + 1)^2 = 4.

Next, we take the square root of both sides to remove the square:

  • 3x+1=±23x + 1 = \pm 2, recognizing the positive and negative roots of 4.

We now solve for xx in each case:

  • Case 1: 3x+1=23x + 1 = 2
    Subtract 1 from both sides: 3x=13x = 1
    Divide by 3: x=13x = \frac{1}{3}.
  • Case 2: 3x+1=23x + 1 = -2
    Subtract 1 from both sides: 3x=33x = -3
    Divide by 3: x=1x = -1.

Therefore, the solutions to the original equation are x1=13x_1 = \frac{1}{3} and x2=1x_2 = -1.

Answer

x1=13,x2=1 x_1=\frac{1}{3},x_2=-1