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Solve this system using substitution: y=5x and 7x-3y=32

Solve this system using substitution: y=5x and 7x-3y=32-example-1
User Bokov
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1 Answer

11 votes
11 votes

Solve equation [2] for the variable y

[2] 2y = -5x + 1

[2] y = -5x/2 + 1/2

// Plug this in for variable y in equation [1]

[1] 7x - 3•(-5x/2+1/2) = -5

[1] 29x/2 = -7/2

[1] 29x = -7

// Solve equation [1] for the variable x

[1] 29x = - 7

[1] x = - 7/29

// By now we know this much :

x = -7/29

y = -5x/2+1/2

// Use the x value to solve for y

y = -(5/2)(-7/29)+1/2 = 32/29

Solution :

{x,y} = {-7/29,32/29}

User Simonmorley
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