How do you solve the following system?: x - 3y = 0 , -3x + 7y = 1

1 Answer
EZ as pi
Jun 17, 2016

x = -1 1/2 , and y = (-1)/2

Explanation:

In order to work with these simultaneous equations, I will make the coefficients of the x terms both 3. But it will be easier to have them as additive inverses, (because by adding: -3 +3 = 0)

" "x - 3y = 0 " A"
" "-3x + 7y = 1 " B"

A x 3: " "3x - 9y = 0" "C

B+C: " " -2y = 1 " the x-terms have been eliminated"
" " y = -1/2

If y = -1/2, " subst in A to find x"

x - 3((-1)/2) = 0

x + 3/2 = 0

x = -3/2

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