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:
B. Multiplication or Division property of equality
Step-by-step explanation:
Both sides of the equation have been multiplied by -1. The multiplication property of equality tells you that multiplying both sides of the equation by the same number does not change the truth of the equation (and the variables retain their values).
Manipulating the left side of the equation, we obtain:

Using that

:
She would have a total of 40 stamps.