B

9000026409

Level: 
B
Consider the following equation. \[ |2x - 4| = 5x - 7 \] Solving the equation on the intervals where it is possible to evaluate the absolute value we get equations on partial subintervals as follows. \[\begin{aligned} \text{for }x &\in (-\infty ;2)\colon &\text{for }x &\in [ 2;\infty )\colon & & & & \\ - 2x + 4 & = 5x - 7 &2x - 4 & = 5x - 7 & & & & \\ - 7x & = -11 & - 3x & = -3 & & & & \\x & = \frac{11} {7} &x & = 1 & & & & \end{aligned}\] Find the solution set of the original equation.
\(\left \{\frac{11} {7} \right \}\)
\(\left \{\frac{11} {7} ;1\right \}\)
\(\left \{1\right \}\)
\(\emptyset \)

9000025804

Level: 
B
In the following list identify a true statement on the function \(f\). \[ f(x) = (x + 1)(x + 2)(x - 3) \]
The function \(f\) is positive on \(I_{1} = (-2;-1)\) and \(I_{2} = (3;\infty )\).
The function \(f\) is an increasing function (in its whole domain).
The function is decreasing only on \(I = (-1;3)\).
The function is decreasing on \(I_{1} = (-\infty ;-2)\) and \(I_{2} = (3;\infty )\).