Marta tried solve the system below, but she made a mistake. Read carefully and try to figure out what her mistake was. Finding Mistakes in a Solution
What was Marta’s mistake? Explain.

Which statement is not always true for a parallelogram? (a) opposite sides are congruent. (b) diagonals bisect each other. (c) it has 4 congruent angles. (d) consecutive angles are supplementary.

Which of the following expressions are equivalent ?

The train station clock runs too fast and gains 5 minutes every 10 days. how many minutes and seconds will it have gained at the end of 9 days?