Question 369668
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Hi,
solving the system x+y=20 and x-y=28, using the 'substitution' method:
1) choose one of the equations to solve for one of the variables
x - y = 28
x = y + 28
2) 'substitute' these findings for x into the other equation x+y=20 
y + 28 + y =20 
solve for y
2y = -8
y = -4
Finding x
x = y + 28 = -4 + 28 = 24
ordered pair( 24,-4) is the point these lines have in common