VARIATION: Find all real solutions to the equation: √(variable_93 + 3 - 4√(variable_93 - 1)) + √(variable_93 + 8 - 6√(variable_93 - 1)) = 1. Find the numerical value if exact

Answer: The real solutions are x∈[5,10]x \in [5, 10].

Step-by-step solution

Step 1: Simplify the terms under the square roots

We observe that the expressions under the square roots resemble the expansion of a perfect square (a−b)2=a2−2ab+b2(a-b)^2 = a^2 - 2ab + b^2. Let a=x−1a = \sqrt{x-1}. Then for the first term, we have x+3−4x−1=(x−1)−4x−1+4=(x−1)2−2(2)(x−1)+22=(x−1−2)2x+3-4\sqrt{x-1} = (x-1) - 4\sqrt{x-1} + 4 = (\sqrt{x-1})^2 - 2(2)(\sqrt{x-1}) + 2^2 = (\sqrt{x-1} - 2)^2. Similarly, for the second term, x+8−6x−1=(x−1)−6x−1+9=(x−1)2−2(3)(x−1)+32=(x−1−3)2x+8-6\sqrt{x-1} = (x-1) - 6\sqrt{x-1} + 9 = (\sqrt{x-1})^2 - 2(3)(\sqrt{x-1}) + 3^2 = (\sqrt{x-1} - 3)^2.

Step 2: Apply the property a2=∣a∣\sqrt{a^2} = |a|

Using the property that a2=∣a∣\sqrt{a^2} = |a|, we can simplify the equation to involve absolute values. This gives us the sum of two absolute value expressions equal to 1.

Step 3: Define a substitution and analyze cases

To simplify the problem, let's substitute y=x−1y = \sqrt{x - 1}. Since x−1x-1 must be non-negative for x−1\sqrt{x-1} to be real, we have x≥1x \ge 1, which implies y≥0y \ge 0. We need to consider different cases for yy based on the critical points y=2y=2 and y=3y=3.

Step 4: Solve for yy in different cases

We analyze three cases for yy: \\ 1. If y<2y < 2, then y−2y-2 is negative and y−3y-3 is negative. The equation becomes −(y−2)−(y−3)=1-(y-2) - (y-3) = 1, which simplifies to −2y+5=1-2y+5=1, giving y=2y=2. This contradicts our assumption y<2y<2. \\ 2. If 2≤y≤32 \le y \le 3, then y−2y-2 is non-negative and y−3y-3 is non-positive. The equation becomes (y−2)−(y−3)=1(y-2) - (y-3) = 1, which simplifies to 1=11=1. This is always true, so all values of yy in the interval [2,3][2, 3] are solutions. \\ 3. If y>3y > 3, then y−2y-2 is positive and y−3y-3 is positive. The equation becomes (y−2)+(y−3)=1(y-2) + (y-3) = 1, which simplifies to 2y−5=12y-5=1, giving y=3y=3. This contradicts our assumption y>3y>3. \\ Therefore, the solution for yy is 2≤y≤32 \le y \le 3.

Step 5: Substitute back to find xx

Now we substitute back y=x−1y = \sqrt{x - 1} into the inequality 2≤y≤32 \le y \le 3.

Step 6: Solve for xx

To solve for xx, we square all parts of the inequality. This gives 4≤x−1≤94 \le x - 1 \le 9. Then, we add 1 to all parts of the inequality to isolate xx, resulting in 5≤x≤105 \le x \le 10. This is the range of all real solutions for xx.

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