+934 hugo, you are also missing the negative solution... (-10)^2 = 100 and (10)^2 = 100. So if c - 3 = -10, then c can also equal -7.
+1009 Take square root on both sides giving
c-3 = 10
c = 10+3 = 13.
Ask if you don't understand anything :)
+934 hugo, you are also missing the negative solution... (-10)^2 = 100 and (10)^2 = 100. So if c - 3 = -10, then c can also equal -7.
