16. Solve the system of equations using the substitution method: (10 points) \begin{cases} -2x + 5y = 15 \ x - 2y = -6 \end{cases} 17. Solve the system of equations using the addition method (elimination): \begin{cases} -3x + 5y = 15 \ 2x + 2y = 6 \end{cases} 18. Name three things from the Math 81 Discussion postings that you may be able to use in future classes to improve your learning experience and results. Write a short paragraph explaining why you think these ideas might be useful. (Counts as two problems on this exam)
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2(2y + 6) + 5y = 15 4y + 12 + 5y = 15 9y + 12 = 15 Step 3: Simplify the equation. 9y = 15 - 12 9y = 3 Step 4: Solve for y. y = 3/9 y = 1/3 Step 5: Substitute the value of y into the second equation to find x. x = 2(1/3) + 6 x = 2/3 + 6 x = 2/3 + 18/3 x = Show more…
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