Answer:
B. x = 4 and x = -10
Step-by-step explanation:
First, expand the equation
(x + 3)² = 49
(x + 3)(x + 3) = 49
x² + 6x + 9 = 49
Subtract 49 from both sides
x² + 6x -40 = 0
Factor
(x + 10)(x - 4) = 0
Solve
x + 10 = 0
x = -10
x - 4 = 0
x = 4
So, the correct answer is B. x = 4 and x = -10
Total number of marbles = 10
Number of red marbles = 4
Number of blue marbles = 6
Probability = 
The probability that the first marble is blue = 
The probability that the first marble is red =
; 9 because 1 marble has already been taken out.
Joint probability= probability of event A * Probability of event B
=
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