Answer:
4
Step-by-step explanation:
The left side of the equation can be factored as the difference of squares:
(a -b)(a +b) = 105
The right side of the equation can be factored to 4 different pairs of factors:
105 = 1·105 = 3·35 = 5·21 = 7·15
For each of the factor pairs, we can match factors to get, for example, ...
a -b = 1
a +b = 105
The solution to this is a = (105 +1)/2 = 53, b = (105 -1)/2 = 52. Thus, we have ...
(a, b) = (53, 52)
For the other factor pairs, the solutions are ...
(a, b) = (19, 16), (13, 8), (11, 4)
There are a total of 4 positive integer solutions.
Hello!
1. -4x2 + 8x + 32
-4(x2 - 2x - 8)
-4(x2 + 2x - 4x - 8)
-4(x(x + 2) - 4(x + 2))
-4(x + 2)(x - 4)
Answer A.
2. 2x2 + 16x + 30
2(x2 + 8x + 15)
2(x2 + 5x + 3x + 15)
2(x(x + 5) + 3(x + 5))
2(x + 5)(x + 3)
Answer C.
Answer:
3.33×10⁴
Step-by-step explanation:
You can use the hint, or you can use a common exponent. Here is the latter case.
(3.9×10⁴) -(5.7×10³) = (3.9×10⁴) -(0.57×10⁴) = (3.9 -0.57)×10⁴
= 3.33×10⁴
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With a little practice, you can see the effect on exponents of moving the decimal point. Here, we have ...
5.7×10³ = (0.57×10)×10³ = 0.57×(10×10³) = 0.57×10⁴
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When adding or subtracting in scientific notation, all that is required is that the exponents of all the numbers be the same. The hint says make all the exponents be 0. Above, we have chosen to make them all be 4. You could also use 3:
(3.9×10⁴) -(5.7×10³) = (39×10³) -(5.7×10³) = (39 -5.7)×10³
= 33.3×10³ = 3.33×10⁴
