Solve and Compare: Delving into (√x+8)(√x-8)=0 and x²-100=0
Question
Solve each equation separately and find which x is the largest.
(x+8)(x−8)=0
x2−100=0
Video Solution
Solution Steps
00:00Find the largest X
00:03First let's find X from section 1
00:10Find the solutions that make the equation equal to zero
00:18Isolate X
00:23The root of a number will always be greater than or equal to 0
00:26Minus 8 is less than 0, therefore there is no solution in this case
00:30The second possible solution
00:36Isolate X, and square both sides to eliminate the root
00:43This is the solution for X in section 1
00:53Now let's calculate X from section 2
01:00Isolate X
01:11Take the root to find the possible solutions for X
01:15These are the possible solutions for X in section 2
01:18We can see that in section 1 one of the solutions is the largest
01:21And this is the solution to the question
Step-by-Step Solution
To solve each equation separately and find the largest value for x, follow these steps:
Step 1: Solve (x+8)(x−8)=0.
Step 2: Solve x2−100=0.
Step 3: Compare the solutions to determine the largest x.
Now, let's solve each step:
**Step 1**: For the equation (x+8)(x−8)=0, apply the zero-product property:
- x+8=0 or x−8=0.
Solving these, we get:
From x+8=0: x=−8, which has no real solutions since square roots cannot be negative.
From x−8=0: x=8, thus x=82=64.
**Step 2**: For the equation x2−100=0, recognize it as a difference of squares x2−102=0:
- Factoring gives (x−10)(x+10)=0.
Solving these, we find: x−10=0, so x=10. x+10=0, so x=−10.
**Step 3**: Compare the solutions of both equations to determine the largest x:
- From Step 1, the valid solution is x=64.
- From Step 2, the valid solutions are x=10 and x=−10.
The largest x is 64 from the solutions obtained.