A

9000020408

Level: 
A
Which of the given equations have at least one root the same? \[ \begin{aligned} x^{2} + 8x + 15 & = 0 &\text{(1)} \\x^{2} - 8x + 15 & = 0 &\text{(2)} \\x^{2} +\phantom{ 8}x - 12 & = 0 &\text{(3)} \\x^{2} - 2x -\phantom{ 1}8 & = 0 &\text{(4)} \\\end{aligned}\]
equations (2) and (3)
equations (1) and (3)
equations (2) and (4)
Such a pair does not exist.

9000020006

Level: 
A
Identify a true statement referring to the solution of the following equation. \[ \sqrt{3x - 8} = x - 6 \]
The equation has a unique solution and this solution is an odd number.
The equation has two solutions, the sum of these solutions is divisible by \(5\).
The equation has a unique solution and this solution is an even number.
The equation does not have a solution in \(\mathbb{R}\).

9000020007

Level: 
A
Identify a true statement referring to the solution of the following equation. \[ \sqrt{x^{2 } - 4} = x + 1 \]
The equation does not have a solution in \(\mathbb{R}\).
The equation has a unique negative solution.
The equation has a unique positive solution.
The equation has two solutions.

9000020008

Level: 
A
Identify a true statement referring to the solution of the following equation. \[ 6x - 13\sqrt{x} + 6 = 0 \] Hint: Use the substitution \(y = \sqrt{x}\).
The solutions \(x_{1}\) and \(x_{2}\) satisfy \(x_{1} = \frac{1} {x_{2}} \).
The equation has a unique solution \(x_{1}\). This solution satisfies \(x_{1} < 1\).
The equation has a unique solution \(x_{1}\). This solution satisfies \(x_{1} > 1\).
The equation does not have a solution in \(\mathbb{R}\).