A nurse is performing a pre-assessment before a patient is seen by a physician. The patient’s weight is inaccurate due to the calibration of the scale.
The patient’s temperature changes during the pre-assessment.
The nurse measures the patient’s weight twice and observes two different measurements.
The nurse estimates the patient’s weight based on the increments on the scale.

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.