Question

Select all equations that have the solution x = 7.
3(x - 5) = 1 + 5(x - 6)
60 = 4(x + 8)
6(2x - 1) - 12 = -2(x + 10)
2(x + 7) = 28

Answer 1

method 1 : sub x = 7 into each one and see if it makes the statement true.
e.g. for 60 = 4(x+8)
LS = 60
RS = 4(7+8) = 4(15) = 60
= LS
so x = 7 is a solution for
60 = 4(x+8)

test the others in the same way

method 2:
actually solve each equation to see if x = 7
e.g.
3(x - 5) = 1 + 5(x - 6)
3x - 15 = 1 + 5x - 30
-2x = -14
x = 7 , we have another winner!

etc