Xy = 6
x + y = 9
x + y = 9
x - x + y = -x + 9
y = -x + 9
xy = 6
x(-x + 9) = 6
x(-x) + x(9) = 6
-x² + 9x = 6
-x² + 9x - 6 = 0
-1(x²) - 1(-9x) - 1(6) = 0
-1(x² - 9x + 6) = 0
-1 -1
x² - 9x + 6 = 0
x = -(-9) ± √((-9)² - 4(1)(6))
2(1)
x = 9 ± √(81 - 24)
2
x = 9 ± √(57)
2
x = 4.5 ± 0.5√(57)
x + y = 9
4.5 ± 0.5√(57) + y = 9
- (4.5 ± 0.5√(57)) - (4.5 ± 0.5√(57))
y = 4.5 ± 0.5√(57)
(x, y) = (4.5 ± 0.5√(57), 4.5 ± 0.5√(57))
The two numbers that multiply to 6 and add up to 9 are 4.5 ± 0.5√(57).
Without needing fancy formulas, we can conclude that after 10 years, half of the substance will be left. So, we can make our own formula:
amount remaining = 1 / 2^(years/10)
So, after 5 years
amount remaining = 1 / 2^(5/10)
amount remaining = 1 / 2^(.5)
amount remaining = 1 /
<span>
<span>
<span>
1.414213562
</span>
</span></span><span>amount remaining = 0.70711 * 20 grams
</span><span><span><span><span>amount remaining = </span>14.1421356237 grams
</span></span></span>
Answer:
2
Step-by-step explanation:
33 photos in a 4x to 7x ratio
4x + 7x = 33
11x = 33
x = 3
33 photos can be put in a 4(3) to 7(3) ratio
which is a 12 to 21 ratio
so 12 photos on one side, and 21 on the other side to get the ratio of 4 to 7
Note:
<span>a(b) = ab = a x b = a times b</span>
