In the system of equations below, a and b are constants. For which of the following values of a and b does the system of equations have exactly two
real solutions?
y = 3
y = ax2 + b
O a = -2, b = 4
O a = 4, b = 3
O a = -2, b = 2
O a = 2, b = 4

Statements reasons 1. ab ≅ cd; ad ≅ bc 1. given 2. ac ≅ ac 2. reflexive property 3. △adc ≅ △cba 3. ? 4. ∠dac ≅ ∠bca; ∠acd ≅ ∠cab 4. cpctc 5. ∠dac and ∠bca are alt. int. ∠s; ∠acd and ∠cab are alt. int. ∠s 5. definition of alternate interior angles 6. ab ∥ cd; ad ∥ bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3?