3a - 4b = 21
check (-2 , -3)
3(-2) -4(-3) =21
-6 +12 = 21
6 does not = 21 so NO
check (0 , 7)
3(0) -4(7) =21
0-28=21
-28 does not equal 21 so NO
check (-3 , -2)
3(-3) -4(-2) =21
-9 +8 = 21
1 does not = 21 so NO
check (7 , 0)
3(7) -4(0) =21
21 = 21
Choice D
Answer:
o.42
Step-by-step explanation:
Since each trial has the same probability of success,
Let, <span><span><span>Xi</span>=1</span></span> if the <span><span>i<span>th</span></span></span> trial is a success (<span>0</span> otherwise). Then, <span><span>X=<span>∑3<span>i=1</span></span><span>Xi</span></span><span>X=<span>∑<span>i=1</span>3</span><span>Xi</span></span></span>,
and <span><span>E[X]=E[<span>∑3<span>i=1</span></span><span>Xi</span>]=<span>∑3<span>i=1</span></span>E[<span>Xi</span>]=<span>∑3<span>i=1</span></span>p=3p=1.8</span><span>E[X]=E[<span>∑<span>i=1</span>3</span><span>Xi</span>]=<span>∑<span>i=1</span>3</span>E[<span>Xi</span>]=<span>∑<span>i=1</span>3</span>p=3p=1.8</span></span>
So, <span><span>p=0.6</span><span>p=0.6</span></span>, and <span><span>P{X=3}=<span>0.63</span></span><span>P{X=3}=<span>0.63</span></span></span>
I thought what I did was sound, but the textbook says the answer to (a) is <span>0.60.6</span> and (b) is <span>00</span>.
Their reasoning (for (a)) is as follows:
Answer:
f(x) and g(x) are inverses
Step-by-step explanation:
* Lets check the inverse function
- If f(x) = y has a domain = x and a range = y, then f^-1 is the
inverse of f with a domain = y and a range = x
- f(x) = f^-1(x) = x
* Now lets solve the problem
∵ f(x) = 8/x
∵ g(x) = 8/x
∴ fg(x) = f(8/x)
∴ fg(x) = 8/(8/x) = 8 ÷ 8/x ⇒ change division sign to the multiplication
sign and reciprocal the fraction after the division sign
∴ fg(x) = 8 × x/8 = x
* Now lets find gf(x)
∴ gf(x) = g(8/x)
∴ gf(x) = 8/(8/x) = 8 ÷ 8/x
∴ gf(x) = 8 × x/8 = x
∵ f(x) = f^-1(x) = x
* fg(x) = gf(x) = x
∴ f(x) and g(x) are inverses