Solve x²-49=0 vs x²+49=0: Finding the Largest X-Value

Solve each equation separately and find which x is the largest.

  1. x249=0 x^2-49=0

  2. x2+49=0 x^2+49=0

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Step-by-step video solution

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00:00 Find the largest X
00:03 First let's find X from section 1
00:08 Let's isolate X
00:13 Take the root to find X
00:23 These are the possible solutions for X from section 1
00:26 Now let's calculate X from section 2
00:32 Let's isolate X
00:41 Any number squared is always greater than 0
00:46 Minus 49 is less than 0 therefore section 2 has no solution
00:49 And this is the solution to the problem

Step-by-step written solution

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1

Understand the problem

Solve each equation separately and find which x is the largest.

  1. x249=0 x^2-49=0

  2. x2+49=0 x^2+49=0

2

Step-by-step solution

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

  • Step 1: Solve the first equation x249=0 x^2 - 49 = 0 .
  • Step 2: Solve the second equation x2+49=0 x^2 + 49 = 0 .
  • Step 3: Compare the x x values to determine which is largest.

Now, let's work through each step:

Step 1: Solve x249=0 x^2 - 49 = 0 .

Add 49 to both sides to isolate the square term: x2=49 x^2 = 49 .

Take the square root of both sides to find x x :
x=±49 x = \pm \sqrt{49}
x=±7 x = \pm 7 .

So, the solutions are x=7 x = 7 and x=7 x = -7 .

Step 2: Solve x2+49=0 x^2 + 49 = 0 .

Subtract 49 from both sides to isolate the square term: x2=49 x^2 = -49 .

Take the square root of both sides considering complex numbers:
x=±49 x = \pm \sqrt{-49}
Using imaginary numbers: x=±7i x = \pm 7i .

These solutions are non-real complex numbers.

Step 3: Compare the solutions.

For the first equation, the real solutions are x=7 x = 7 and x=7 x = -7 .

Since the second equation only has imaginary solutions, the largest real x x is from the first equation: x=7 x = 7 .

Therefore, the largest x x is 7.

3

Final Answer

1

Practice Quiz

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Solve the following equation:


\( 2x^2-8=x^2+4 \)

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