Alloy, c, weighing 500 ounces and having 35% aluminum, is obtained from melting together x ounces of alloy, a, containing 25% aluminum, and y ounces of alloy, b, containing 40% aluminum. write an equation showing the ounces of alloy a and b that can be used to obtain alloy c.

From the given scenario in this item, we can say that the sum of x and y is 500. By the aluminum balance, the equation that we can formulate from this,
                            0.25x + 0.40y = (500)(0.35)
The system of linear equations that can best express the given is,
                                   x + y = 500
                                0.25x + 0.40y = 175

The answer is 10. and if you go by pemdas you would 1. multiplication 2. division 3. addition 4. subtraction

Heptagon is the correct ans