Week 5 discussion.docx - Math 114N Week 5 Discussion Systems of Equations in the Real World Initial Post Instructions If you have a problem that has

# Week 5 discussion.docx - Math 114N Week 5 Discussion...

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Math 114N Week 5 Discussion: Systems of Equations in the Real World Initial Post Instructions If you have a problem that has multiple variables, you can solve it using a system of equations. Think of a real-world example where you would need to solve using a system of equations. Write two or three sentences describing your example. Include the equations in your description, but do not solve the system. That will be left to your classmates . For this week's discussion we are going over system of equations. My example of such is My sister and I decided to go to Mcdonalds for dinner. I ordered 3 hot and spicy sandwiches and 3 medium fry that totaled to \$11.25. My sisters total for 4 hot and spicy sandwiches and 2 medium fry was \$10. How much do the hot and spicy sandwiches and medium fry cost independently. Our variables will be: x= cost of a hot and spicy y= cost of a medium fry So for my dinner in equation form: 3 hot and spicys and 3 medium fry will cost= \$11.25 3x+3y=11.25 My sisters order in equation form: 4 hot and spicys and 2 medium fry=\$10 4x+2y=10
Now to find the price of each item I need to rewrite the equation with opposite teams to find the x value. So: 2[3x+3y=11.25] 2[3x+3y=11.25] 6x+6y=22.50 6x+6y=22.50 and −3[4x+2y=10] −3[4x+2y=10] −12x−6y=−30 −12x−6y=−30 now we will combine −12x−6y=−30 −12x−6y=−30 6x+6y=22.50 6x+6y=22.50 −6x=−7.50 −6x=−7.50 −6=−6 −6=−6 x=1.25 x=1.25 Now to find y 4x+2y=10 4x+2y=10 4(1.25)+2y=10 4(1.25)+2y=10 5+2y=10 5+2y=10
5−5+2y=10−5 5−5+2y=10−5 (subtract by 5 on both sides) 2y=5 2y=5 (divide by 2) y=2.5 y=2.5 So one hot and spicy will cost \$1.25 and one medium fry will cost \$2.50