Aquadratic function has the form y=ax^2 for some non-zero value of a and (4,48) is on the graph. what is the value of a?

Ametalworker has a metal alloy that is 30? % copper and another alloy that is 55? % copper. how many kilograms of each alloy should the metalworker combine to create 90 kg of a 50? % copper? alloy?

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

Two times a number plus three times another number equals 4. three times the first number plus four times the other number is 7. find the numbers