How do I solve 12x+7y=3100 without guessing and checking

Beverly places a gift into a box of equal dimensions and realizes the box is too small. She needs a box with dimensions that are 9 centimeters more than 2 times the dimensions of the first box.

Simplify the expression: cos^2 (pi-x) / sqrt1-sin^2 (x) A. Tan (x) B. Cos (x) tan (x) C. Cos (x) cot (x) D. Sin (x) tan (x)

What's the problem 13.64:7=

It is estimated that 20 patrons will attend an event for every $100 spent in advertising. If tickets cost $40, how much can a promoter expect to increase sales if he spends $10,000 in advertising?

A researcher wants to see if there is a difference in the number of emplyees at a company scheduled to work on a specific bridge. At alpha =.05, is there a difference in the average number of employees working at each bridge?

Is 6/8 is greater than or less than 2/3

How much greater is 113,998 than 97,813

Molly purchased 7 apples for $3.96. while looking at her receipt, Molly divided three $3.96 by 7. why might Molly perform this calculation?

Which statement is true about millimeters and kilometers?

A bag contains of cards 2 red 3yellow, 3 blue What is the probability that you will draw a red card and then a yellow card