Answer: Never true.
Step-by-step explanation: Distribute the numbers: 4 times x is 4x, 4 times 3 is 12. Then you have the equation: -x+4x +12 = -12. Now, choose a random number, maybe -4. A negative plus a negative cancels out so you are left with 4-16(Because you distribute the number) +12 = -12. 4-16 is -12. -12 plus 12 equals 0.
V = (4/3) pi r^3
9. V = (4/3)(3.14)(7.62)^3 = 1852.4 meters^3
10. V = (4/3)(3.14)(33/2)^3 = 18,807.0 inches^3
11. V = (4/3)(3.14)(18.4/2)^3 = 3260.1 feet^3
12. V = (4/3)(3.14)(sqrt3)/2)^3 = 2.7 cm^3
13. C = 2*pi*r ; 24 = 2 * 3.14 * r; 24/6.28 = r ; r = 3.82
V = (4/3)(3.14)(3.82)^3 = 233.4 in^3
14.V = (4/3)(3.14)(35.8)^3 = 192,095.6 mm^3
I can't read # 15 but follow the steps above.
A) .10 d + .25 q = 7.75
B) d + q = 40
Multiplying B) by -.10
B) -.10d -.10q = -4.0
Then adding this to A)
A) .10 d + .25 q = 7.75
.15q = 3.75
Quarters = 25
Therefore, dimes = 15
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Double-Check
A) .10 d + .25 q = 7.75
A) .10 * 15 d + .25 * 25 = 7.75
A) 1.50 + 6.25 = 7.75
Correct!!
If y = cos(kt), then its first two derivatives are
y' = -k sin(kt)
y'' = -k² cos(kt)
Substituting y and y'' into 49y'' = -16y gives
-49k² cos(kt) = -15 cos(kt)
⇒ 49k² = 15
⇒ k² = 15/49
⇒ k = ±√15/7
Note that both values of k give the same solution y = cos(√15/7 t) since cosine is even.
