How do you solve the system of equations #3x+y=10# and #y=2x#?

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Answer 1 · 2018-03-15T16:39:07

See a solution process below:

Step 1) Because the second equation is already solved for #y# we can substitute #(2x)# for #y# in the first equation and solve for #x#:

#3x + y = 10# becomes:

#3x + 2x = 10#

#(3 + 2)x = 10#

#5x = 10#

#(5x)/color(red)(5) = 10/color(red)(5)#

#(color(red)(cancel(color(black)(5)))x)/cancel(color(red)(5)) = 2#

#x = 2#

Step 2) Substitute #2# for #x# in the second equation and calculate #y#:

#y = 2x# becomes:

#y = 2 * 2#

#y = 4#

The Solution Is:

#x = 2# and #y = 4#

Or

#(2, 4)#