Question

What is the solution set of 7x^2 + 3x = 0?
A. {0, 3/7}
B. {0, -3/7}
C. {0, -4/7}

Answer 1

7x² + 3x = 0

x(7x + 3) = 0 ⇔ x = 0 or 7x + 3 = 0    |subtract 3 from both sides

x = 0 or 7x = -3    |divide both sides by 7

x = 0 or x = - 3/7

Answer: B. {0; -3/7}

Answer 2

to solve the solution set of the problem, we can factor the expression given into x* ( 7x + 3 ) = 0. This dissects the equation into two parts: 
x = 0 
and 
7x + 3 = 0x = -3/7 
Hence the answer to this problem must be B.  {0, -3/7}