Question #f9676

1 Answer
Sep 2, 2017

You could use substitution (y = 1 - x) or linear systems.

Explanation:

Write the two equations as a linear system. Use algebraic properties to find the unknowns. A linear system can be solved as long as there are at least as many independent equations as there are variables.
#2x = 5y#
#x + y = 1# First, get all of the variables on one side:
#2x - 5y = 0#
#x + y = 1#; Now multiply the second equation by 5d and add it to the first one:
#2x - 5y = 0#
#5x + 5y = 5#

#7x = 5#; #x = 5/7#; Substitute this value back into the first equation to find the 'y'.
#2(5/7) = 5y#; # (2/5)(5/7) = y#; #y = 2/7#
CHECK by putting both values into the second equation:

#x + y = 1# ; #5/7 + 2/7 = 1# ; #1 = 1# CORRECT!