Points a and b are midpoints of the sides of triangle qrs. triangle q r s is cut by line segment a b. point a is the midpoint of side q s and point b is the midpoint of side r s. the length of q r is 6 meters, the length of q a is 4 meters, the length of a b is 3 meters, and the length of r b is 3 meters. what is sa?

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.

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