Answer: When the quadratic equation can be factored or solved by completing the square, you do not need to use the quadratic formula
Step-by-step explanation: In the form ax² + bx + c
Whenever <em><u>a</u></em> is 1 (implied, no coefficient of x²) and the constant, <u><em>c</em></u>, is a multiple of numbers whose sum or difference is equal to <u><em>b</em></u>, factoring is much quicker and easier than using the quadratic formula.
Even when there is a coefficient of x², there are procedures to find the factors and solve for x without resorting to the quadratic formula.
Answer:

Step-by-step explanation:
Factor
out of 
Acres = 640 * sq miles
acres = 640 * 3.5
acres = 2,240 square miles
**************************************************************
Incidentally, here's how that 640 acres per square mile is derived.
1 acre = 43,560 square feet
1 square mile = 5,280^2 =
<span>
<span>
<span>
27,878,400
</span>
</span>
</span>
square feet
<span>
<span>
27,878,400
</span>
/ 43,560 = 640 acres exactly</span>
Answer:
your answer would be 9
Step-by-step explanation:
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