Solve the Quadratic Equation: x²/2 + x - 4 = 0 Step-by-Step

Question

Solve the following equation:

x22+x4=0 \frac{x^2}{2}+x-4=0

Video Solution

Solution Steps

00:00 Find X
00:03 Multiply by 2 to eliminate fractions
00:13 Identify the coefficients
00:21 Use the roots formula
00:37 Substitute appropriate values according to the given data and solve
01:05 Calculate the square and products
01:15 Calculate the square root of 36
01:30 These are the 2 possible solutions (addition,subtraction)
01:44 And this is the solution to the question

Step-by-Step Solution

To solve the equation x22+x4=0 \frac{x^2}{2} + x - 4 = 0 , we'll use the quadratic formula. First, we need to rewrite the equation in standard quadratic form, ax2+bx+c=0 ax^2 + bx + c = 0 .

Start by multiplying the entire equation by 2 to eliminate the fraction:

 x2+2x8=0\ x^2 + 2x - 8 = 0

Now, identify the coefficients:

  • a=1 a = 1
  • b=2 b = 2
  • c=8 c = -8

Next, plug these coefficients into the quadratic formula:

 x=b±b24ac2a\ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

Substitute a=1 a = 1 , b=2 b = 2 , and c=8 c = -8 into the formula:

 x=2±2241(8)21\ x = \frac{-2 \pm \sqrt{2^2 - 4 \cdot 1 \cdot (-8)}}{2 \cdot 1}

Simplify inside the square root first:

 2241(8)=4+32=36\ 2^2 - 4 \cdot 1 \cdot (-8) = 4 + 32 = 36

Substitute back:

 x=2±362\ x = \frac{-2 \pm \sqrt{36}}{2}

The square root of 36 is 6, so:

 x=2±62\ x = \frac{-2 \pm 6}{2}

Calculate the two possible solutions:

1. x1=2+62=42=2 x_1 = \frac{-2 + 6}{2} = \frac{4}{2} = 2 2. x2=262=82=4 x_2 = \frac{-2 - 6}{2} = \frac{-8}{2} = -4

Therefore, the solutions for the equation x22+x4=0 \frac{x^2}{2} + x - 4 = 0 are x1=2 x_1 = 2 and x2=4 x_2 = -4 .

Answer

x1=2,x2=4 x_1=2,x_2=-4