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7x + 10y = 36 y= -2x+9

1 Answer

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Explanation:

Consider this equality as two separate equations:

7x+10y=36y

36y=-2x+9

Now, we have a system of equations. Let's use substitution method to solve. Substitution method involves solving one equation for a variable--then plugging that result into the other equation.

Let's solve 36y=-2x+9 for x:

36y=-2x+9 (Given)

36y-9=(-2x+9)-9 (Subtraction Property of Equality)

36y-9=-2x (Simplification)

(36y-9)/(-2)=(-2x)/(-2) (Division Property of Equality)

-18y+(9/2)=x (Simplification)

Now, we get to substitute -18y+(9/2) for x into the other equation:

7x+10y=36y (Given)

7(-18y+(9/2))+10y=36y (Substitution)

-126y+(63/2)+10y=36y (Distributive Property)

-126y+10y+(63/2)=36y (Commutative Property of Addition)

-116y+(63/2)=36y (Simplification)

(-116y+(63/2))+116y=36y+116y (Addition Property of Equality)

63/2=152y

(63/2)/152=(152y)/152 (Division Property of Equality)

63/304=y (Simplification)

Yay, after all that hard work, we've finally found one of our variables! :) Now, we've just got to substitute our y value into one of the original equations. That way, we can solve for x.

Let's substitute into 36y=-2x+9:
36y=-2x+9 (Given)

36(63/304)=-2x+9 (Substitution)

(2268/304)=-2x+9 (Simplification)

(2268/304)-9=(-2x+9)-9 (Subtraction Property of Equality)

(2268/304)-9=-2x (Simplification)

(2268/304)-9(304/304)=-2x (Common Denominators on Left Side)

(2268/304)-(2736/304)=-2x (Simplification)

(-468/304)=-2x (Simplification)

(-468/304)/(-2)=(-2x)/(-2) (Division Property of Equality)

234/304=x (Simplification)

117/152=x (Simplification)

Our final answers are x=117/152 and y=63/304.

Answer: x=117/152 and y=63/304

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