Question

Zhang Li solves the equation below by first squaring both sides of the equation. -4=\sqrt{5z+7}−4= 5z+7 ​ minus, 4, equals, square root of, 5, z, plus, 7, end square root What extraneous solution does Zhang Li obtain?

Answer 1

z=9/5

Explanation:

-4= √(5z+7)

squaring both sides of the equation

(-4)²= (√(5z+7))²

16= 5z+7

16-7 =5z

9=5z

z=9/5