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Zorluk: KolaySystems of Linear Equations

In the system of equations below, what is the value of yy?

4x+3y=254x + 3y = 25
2x+3y=172x + 3y = 17

Cevap: 3

Cevap

The value of yy is 33.
Subtracting the second equation from the first equation gives (4x+3y)(2x+3y)=2517(4x + 3y) - (2x + 3y) = 25 - 17, which simplifies to 2x=82x = 8. Dividing by 2 gives x=4x = 4. Substituting x=4x = 4 into the second equation gives 2(4)+3y=172(4) + 3y = 17, which simplifies to 8+3y=178 + 3y = 17. Subtracting 8 from both sides gives 3y=93y = 9, and dividing by 3 gives y=3y = 3.

Adım Adım Çözüm

1
Subtract the second equation from the first equation to eliminate the yy term.
2x=82x = 8
Subtracting the equations eliminates 3y3y since it is common to both equations, leaving a single variable equation.
2
Solve for xx by dividing both sides of the equation by 2.
x=4x = 4
Dividing isolates the variable xx so we can find its numerical value.
3
Substitute x=4x = 4 into the second equation 2x+3y=172x + 3y = 17 and solve for yy.
y=3y = 3
Substituting the value of xx leaves only the variable yy, which can then be isolated and solved.

Anahtar Kavram

Solving systems of linear equations using elimination
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