What does x represent?

15x-12y=13

30x+9y=4

What is the definition of principal square root in math?

1. A U. S. student studied abroad in Zürich, Switzerland. When he arrived in Zürich in January 2005, he exchanged $20,000 for Swiss francs when the exchange rate of USD/CHF (U. S. dollars to Swiss francs) was 1.15.

What is the discriminant of the polynomial below 4x2+4x+1? A. 32 B. - 4 C. 0 D. - 12

1,258 rounded to the nearest thousand is

The radius of a 10 inch right circular cylinder is measured to be 4 inches, but with a possible error of ±0.1 inch. What is the resulting possible error in the volume of the cylinder? Include units in your answer.

An airplane is flying 35,000 feet above sea level. the airplane starts to descend at a rate of 2,500 feet per minute. let m be the number of minutes.

Divide $12.00 by 16 or find the quotient of an equivalent

Selma wants to know if seventh grade students prefer to do their math homework in silence or with background music. She polled the 30 students in her music class.

Count the total number of atoms in this formula: CH 4

Factor completely 25-80+64