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

1 Answer
Jun 17, 2016

Answer:

#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#