![]() ![]() Here we have two different values for what x could be equal to, so two distinct solutions (we get the y value from plugging each x back into one of the initial equations). One way of solving this is with the quadratic formula: ![]() To solve this, the easiest way to substitute is to put equation 1 into where equation 2 has y:įrom here, we have a quadratic equation. Usually the SAT gets around this by specifying that you're finding the solution where for example y=0 or something like that. The one caveat is that there doesn't have to be just one solution. To solve such a problem, you can try substitution, just like you would for a normal linear equation. These types of questions are pretty rare on the SAT, and you're not guaranteed to see one on every test. If there are differing exponents for x and y, you have a nonlinear system of equations. Together, your equations would look like this:Īnd after solving them, you should hopefully get that machine x operated for 5 1/2 hours and y operated for 9 1/2. We get our second equation just from when the question says that the machines took 15 hours together to produce the 545 parts. Add them together, and we should have 545. 30 * x is the number of parts that the old machine can make in x hours, and 40 * y is the same for the new machine. Since by multiplying a rate by the time taken you get the total amount of work done, we can make an equation from this. We also know that together, they produced 545 parts. In the first part of the question, we learn about how x and y are related in terms of their rates. Here, we're comparing 2 machines, so the time the old one takes could be our "x", and the new one could be "y". With those, you'll be able to create two equations and solve the equations. To get a system of equations from a question, you want to find two separate pieces of information that relate the two variables. ![]()
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