The matrix below represents a system of equations. 2 1 1 4
-3 2 -1 -8
1 -1 1 5
Which matrix represents the solution to this system of equations?

Sal is tiling his entryway. the floor plan is drawn on a unit grid. each unit length represents 1 foot. tile costs $1.35 per square foot. how much will sal pay to tile his entryway? round your answer to the nearest cent.

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.