18 ÷ x = -2 what does x equal

Jackie purchased 3 bottles of water and 2 cups of coffee for a family for $7.35. brian 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? i need this done

Which shows the correct substitution of the values a, b and c from the equation 1=-2x+3x^2+1

The area of square garden is 300m squared. how long is the diagonal?