Answer:
- (b - 9)(b + 8)
Step-by-step explanation:
72 + b - b² ← factor out - 1 from each term and rearrange into standard form
= - (b² - b - 72) ← factor the quadratic
Consider the factors of the constant term (- 72) which sum to give the coefficient of the b- term (- 1)
The factors are - 9 and + 8
Use these factors to split the b- term
b² - 9b + 8b - 72 ( factor the first/second and third/fourth terms )
b(b - 9) + 8(b - 9) ← factor out (b - 9) from each term
(b - 9)(b + 8)
Then
72 + b - b² = - (b - 9)(b + 8)
He can make 3 batches of soup.
Starting with 10 pounds of tomatoes and taking out the number of pounds he sets aside for spaghetti sauce, 2.8, we have:
10-2.8 = 7.2 pounds left.
0.2 is read as "two tenths," so 7.2 = 7 2/10
We divide this remaining number of pounds by 2 2/5 for each batch of soup:
7 2/10 ÷ 2 2/5
Convert each to an improper fraction:
72/10 ÷ 12/5
Multiply by the reciprocal:
72/10 × 5/12 = 360/120 = 3
Answer: Any real number x as long as 
and 
In other words, anything but 0 or -2/3 is valid.
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Explanation:
Set the denominator equal to zero and solve for x
2(3x^2 + 2x) = 0
3x^2 + 2x = 0
x(3x + 2) = 0
x = 0 or 3x+2 = 0 .... zero product property
x = 0 or 3x = -2
x = 0 or x = -2/3
If either x = 0 or x = -2/3, then the denominator 2(3x^2 + 2x) will be zero. But recall that we cannot have zero in the denominator. Dividing by zero is not allowed. The expression is undefined when we divide by zero.
Therefore, we must exclude x = 0 and x = -2/3 from the domain. Any other real number is valid as an x input.
