Simultaneous Equations with Constants? What to do

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WannabeCrypto
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#1
Report Thread starter 3 years ago
#1
Hi can anyone point me in the right direction with this:

5𝑥 +4𝑘𝑦 = 6
3𝑥 −20𝑘𝑦 = 26

are simultaneous equations where k is a constant.

a) Show that 𝑥 = 2
b) Given that 𝑦 = −2, determine the value of 𝑘

I don't know what to do with the constant or what it represents
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K1NGZ
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#2
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try learning to split the middle term
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N/A IS THE NAME
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a) multiply the 1st eq by 5. Add both eq to eliminate ky. solve to find x

b) Use either eq and substitute your x value (you worked out for part a). Substitue y=-2. Solve to find k.
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N/A IS THE NAME
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For future reference, just follow the order of the questions step by step- their just trying to confuse you. All your doing is applying your knowledge.
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RichardM37
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#5
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"N/A IS THE NAME" gave good advice.

It is one of the basic steps for solving N Equations in N Unknowns.
In the present case, multiplying the first equation by 5 allows you to eliminate the ky term. The equations become

25 x + 20 ky = 30
3 x - 20 ky = 26

Now when these equations are added together, the result is

28 x = 56

Solving this equation for x is now simple.

Knowing x, and being given the value for y, either of the original equations can be used to plug these values in to solve for k.
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