When four times a number is added to 8 times the number, the result is 36. What is the number

Gail is making costumes for a school play. each rabbit costume needs one and one half yards of white fur fabric, a yard of blue striped fabric, and a quarter of a yard of pink felt for the ears. g? ail needs to make eight rabbit man yards will she need, for the white fur fabric, blue striped fabric, and pink felt?

Jackie purchased 3 bottles of water and 2 cups of coffee for the family for $7.35. ryan bought 4 bottles of water and 1 cup of coffee for his family for 7.15. how much does each bottle of water cost? how much does each cup of coffee cost?

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?