heartonsleeve

Heh, sorry to be back so soon, I just really suck at math. ^^;;

Can someone help me with question #10 on pg 370, #3 on pg 373 and #6 and 7 on pg 374?

Thanks!€

tomahawk89

#10 on p. 370 is (E) because k=f(3), and according to the table, f(3)=4. Therefore, k=4, and g(k), which becomes, g(4)=5. I'm working on the other problems.

tomahawk89

#6 on p. 374 is 5 because the slope of a line that passes through points (a,b) and (c,d) is (d-b)/(c-a), which is, in this case, (-2-0)/(1-a)=1/2, which becomes (1-a)*1=-2*2, and 1-a=-4, therefore a=5.

tomahawk89

#7 on p. 374 is 2/7. Let's say that the arithmetic mean of all children's weight is w, then the sum of all the weights would be 10w. And since the adult's weight is 4 times greater than w, it's 4w. So the whole sum of all people in the elevator would be 14w. If you divide the adult's weight, 4w, by the entire weight of the people, 14w, you get 4w/14w=2/7.

tomahawk89

#3 on p. 373 is 2. Since (x+1/x)=2, and (x+1/x)^2=4. If you expand it, you'll get x^2+2+1/x^2=4, and if you subtract both sides of the equation by 2, you will end up getting x^2+1/x^2=2.

heartonsleeve

Thanks!! I really appreciate it.

llpitch

EDIT: tomahawk89's answer to #3 is incorrect. See below for the answer.

3. If x+(1/x)=2, what is the value of x^2+(1/x^2)?

The correct answer to #3 is that because x+(1/x)=2, (x^2+1/x)=2. Multiply x over and then make the equation equal to 0. You get x^2-2x+1=0. Then just factor it out and you get (x-1)(x-1)=0. Therefore x = 1. Plug x=1 into x^2+(1/x^2) and you 2 as the answer.