By: Drake Hudspeth 03/07/11 Math-03 x=algebra The substitute is in! By: Drake Hudspeth 03/07/11 Math-03
The Problem Equations- 3x+y=38 3x+2y=52 The school that Stefan goes to is selling tickets to a choral performance. On the first day of ticket sales the school sold three senior citizen tickets and one child ticket for a total of 38$. The school took in 52$ on the second day by selling three senior citizen tickets and two child tickets. Find the price of a senior citizen ticket and the price of a child ticket. Equations- 3x+y=38 3x+2y=52
Graphing Use Microsoft Excel. Plot your point in cells B2 and C2-B8 and C8. Use cell A1 to put x. In A2-A8 put -5,-3,-1,0,1,3,and5. Put your equation in cells B1 and C1. Go to insert and choose graphs. Pick the x and y graph. The reason that I do not recommend this system is because there is no way to go back and see why you missed the answer and because you must first solve for y.
Substitution Start with one equation. 3x+y=38 Subtract the x on both sides. 3x-3x+y=38-3x You now use this y on the next equation. 3x+2(38-3x)=52 Distribute or multiply what is outside of the parenthesis with what is inside of it. 3x+76-6x=52 Combine like terms. -3x=-24 Divide the two terms that you have. X=8 Use x to solve for y. 3(8)+y=38 Distribute. 24+y=38 Subtract the integer on the left from the integer on the right. 38-24=14 You now have y. y=14 So x=8 and y=14. I enjoy this method because it is accurate and there are many steps to see where you have made a mistake.
Elimination You must use both equations in the beginning. First subtract one integer from the other. (3x+2y=52)-(3x+y=38). You now have y=14. Now plug y=14 into one equation. 3x+2(14)=52 Distribute. 3x+28=52 Subtract the integer on the left from the integer on the right. 52-28=24 You should now have 3x=24. Now divide. 24/3=8 y=14 and x=8 This method is okay to use but it will not always be this simple.