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What is the solution to the system of equations 3x+5y=-1
6x - 4y = 26 ?

User Dilettant
by
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1 Answer

2 votes

Answer: 7 9/34 or 7.264705882

Step-by-step explanation:

3x+5y=−16x−4y=26

Consider the first equation. Add 16x to both sides.

3x+5y+16x=−4y

Combine 3x and 16x to get 19x.

19x+5y=−4y

Add 4y to both sides.

19x+5y+4y=0

Combine 5y and 4y to get 9y.

19x+9y=0

To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation

19x+9y=0,−16x−4y=26

Choose one of the equations and solve it for x by isolating x on the left hand side of the equal sign.

19x+9y=0

Subtract 9y from both sides of the equation.

19x=−9y

Divide both sides by 19.

x= 1/19 (-9)y

Multiply 1/19 times -9y

x= -9/19y

Substitute - 9y/19for x in the other equation, −16x−4y=26.

-16 (-9/19) y - 4y = 26

Multiply −16 times -9y/19

144/19 y -4y -26

Add 144y/19 to -4y

68/19y = 26

Divide both sides of the equation by 68/19 which is the same as multiplying both sides by the reciprocal of the fraction.

y = 247/34

Substitute 247/34 for y in x = -9/19y Because the resulting equation contains only one variable, you can solve for x directly.

x = - 9/19 x (247/34)

Multiply - 9/19 times 247/34 by multiplying numerator times numerator and denominator times denominator. Then reduce the fraction to lowest terms if possible

x = - 117/34

The system is now solved.

x = - 117/34 , y = 247/34

Turned into a mixed number would be

7 9/34.

User Shawn Hoover
by
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