# Substitution Solving,(Assignment),Math-Algebra

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**santiago36**

Last updated 8 years ago

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Finished Assignment Examples
** Grade:**

8

The students will pick one of the following systems of linear equations:Level 1: y=2x and y+3x=12Level 2: y=2x-7 and 2y+x=1Level 3: 2x-y=5 and 3y+9=9xand solve it using the substitution method. The student will be able to use substitution to find an exact solution. The student will describe use prior knowledge to explain how they arrived at their answer.

Assignment

Solving systems of equations using substitution

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Steps

1)We simplify the linear equations if they are not in slope-intercept form, y=mx+b 2)We substitute for the x or y 3)I substituted for the y 4)I plug-in y = 2x-5 for the y in the equation y=3x-32x-5=3x-35)Use Properties Of Equality to simplify the expression by combining like terms.6)Subtraction POE allows us to subtract -2x from both sides. -5=x-37)Addition POE allows us to add +3 to both sides-2=x8)We take our solution for x and plug in to either of the equations. 9)I chose to plug-in the x in the equation 2x-y=52(-2)-y=5-4-y=510)Addition POE allows us to add +4 to both sides-y=911)Division POE allows us to divide -1 to both sidesy=-912)The ordered pair solution is (-2,-9)13)We need to check the solution to see if it is true. We plug-in to either of the equations.I chose 3y+9=9x3(-9)+9=9(-2)-27+9=-18-18=-18 True14)The point (-2, -9) is a solution. This means the lines 2x-y=5 and 3y+9=9x intersect at (-2,-9)

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