4/13 because the absolute value would be itself since it is positive. If it was negative then the absolute value would be positive.
First we'll substitute
with 

Then we can separate this.

Then we'll solve this.



Then we'll plug in to find the extraneous solutions (if any)

Answer:
a) ![P[C]=p^n](https://tex.z-dn.net/?f=P%5BC%5D%3Dp%5En)
b) ![P[M]=p^{8n}(9-8p^n)](https://tex.z-dn.net/?f=P%5BM%5D%3Dp%5E%7B8n%7D%289-8p%5En%29)
c) n=62
d) n=138
Step-by-step explanation:
Note: "Each chip contains n transistors"
a) A chip needs all n transistor working to function correctly. If p is the probability that a transistor is working ok, then:
![P[C]=p^n](https://tex.z-dn.net/?f=P%5BC%5D%3Dp%5En)
b) The memory module works with when even one of the chips is defective. It means it works either if 8 chips or 9 chips are ok. The probability of the chips failing is independent of each other.
We can calculate this as a binomial distribution problem, with n=9 and k≥8:
![P[M]=P[C_9]+P[C_8]\\\\P[M]=\binom{9}{9}P[C]^9(1-P[C])^0+\binom{9}{8}P[C]^8(1-P[C])^1\\\\P[M]=P[C]^9+9P[C]^8(1-P[C])\\\\P[M]=p^{9n}+9p^{8n}(1-p^n)\\\\P[M]=p^{8n}(p^{n}+9(1-p^n))\\\\P[M]=p^{8n}(9-8p^n)](https://tex.z-dn.net/?f=P%5BM%5D%3DP%5BC_9%5D%2BP%5BC_8%5D%5C%5C%5C%5CP%5BM%5D%3D%5Cbinom%7B9%7D%7B9%7DP%5BC%5D%5E9%281-P%5BC%5D%29%5E0%2B%5Cbinom%7B9%7D%7B8%7DP%5BC%5D%5E8%281-P%5BC%5D%29%5E1%5C%5C%5C%5CP%5BM%5D%3DP%5BC%5D%5E9%2B9P%5BC%5D%5E8%281-P%5BC%5D%29%5C%5C%5C%5CP%5BM%5D%3Dp%5E%7B9n%7D%2B9p%5E%7B8n%7D%281-p%5En%29%5C%5C%5C%5CP%5BM%5D%3Dp%5E%7B8n%7D%28p%5E%7Bn%7D%2B9%281-p%5En%29%29%5C%5C%5C%5CP%5BM%5D%3Dp%5E%7B8n%7D%289-8p%5En%29)
c)
![P[M]=(0.999)^{8n}(9-8(0.999)^n)=0.9](https://tex.z-dn.net/?f=P%5BM%5D%3D%280.999%29%5E%7B8n%7D%289-8%280.999%29%5En%29%3D0.9)
This equation was solved graphically and the result is that the maximum number of chips to have a reliability of the memory module equal or bigger than 0.9 is 62 transistors per chip. See picture attached.
d) If the memoty module tolerates 2 defective chips:
![P[M]=P[C_9]+P[C_8]+P[C_7]\\\\P[M]=\binom{9}{9}P[C]^9(1-P[C])^0+\binom{9}{8}P[C]^8(1-P[C])^1+\binom{9}{7}P[C]^7(1-P[C])^2\\\\P[M]=P[C]^9+9P[C]^8(1-P[C])+36P[C]^7(1-P[C])^2\\\\P[M]=p^{9n}+9p^{8n}(1-p^n)+36p^{7n}(1-p^n)^2](https://tex.z-dn.net/?f=P%5BM%5D%3DP%5BC_9%5D%2BP%5BC_8%5D%2BP%5BC_7%5D%5C%5C%5C%5CP%5BM%5D%3D%5Cbinom%7B9%7D%7B9%7DP%5BC%5D%5E9%281-P%5BC%5D%29%5E0%2B%5Cbinom%7B9%7D%7B8%7DP%5BC%5D%5E8%281-P%5BC%5D%29%5E1%2B%5Cbinom%7B9%7D%7B7%7DP%5BC%5D%5E7%281-P%5BC%5D%29%5E2%5C%5C%5C%5CP%5BM%5D%3DP%5BC%5D%5E9%2B9P%5BC%5D%5E8%281-P%5BC%5D%29%2B36P%5BC%5D%5E7%281-P%5BC%5D%29%5E2%5C%5C%5C%5CP%5BM%5D%3Dp%5E%7B9n%7D%2B9p%5E%7B8n%7D%281-p%5En%29%2B36p%5E%7B7n%7D%281-p%5En%29%5E2)
We again calculate numerically and graphically and determine that the maximum number of transistor per chip in this conditions is n=138. See graph attached.
I'm sorry but it's bugging me that you aid 'one cases', you can't have the plural of something that is strictly singular.
Now: for your answer.
72*35=2520
94*23=2162
2520+2162=4682
The total wight is 4682 pounds.
Hope this helps