devils67

#7 on 473

#18 on 412

#14 and 15 on 427

#16 on 475

#17 on 522

#8 on 596

#18 on 657

#15 on 684

Any help would be greatly appreciated.

devils67

bump............

hannanaq

i would help u if i had the book

LoJT

post the questions...

eastsoldier

Same here... put some efforts to type them out please

I just came in, saw the numbers, and went out.

setzwxman

16, p. 475:

h(x) = 14 + (x^2 / 4)
h(2m) = 14 + ((2m)^2 / 4)
h(2m) = 14 + (4m^2 / 4) <---you can cancel the 4s here or get a common denominator and then factor out ... the latter is more work and the former works just fine)

h(2m) = 14 + m^2
Set this = to 9m...

14 + m^2 = 9m
Factor away!
0 = m^2 - 9m + 14
0 = (m - 2)(m - 7)
m = 2, 7 <---CB will accept either one

15, p. 427

Split PQ into 2 segments (since we know a quadratic curve with its axis running along the y-axis will be symmetric about the y-axis... lol)... So we have two segments of length 3. This gives us our x value(s) for the y = x^2 function. f(3) = (3)^2 = 9. Since the other function intersects at this same point, we can set that function = to 9...
9 = a - (3)^2
9 = a - 9
18 = a

7, p. 473 has something to do with breaking the numbers down; some sort of trick that I forget how to do...
8, p. 596 has to do with trying numbers in the expression... Someone can probably provide a better explanation... The answer is 3^3 * 4^2 which = 432.

14, p. 427 ... I just multiplied both sides of the equation by (a - b)^(1/2). Then I squared both sides of the equation, and I got a^2 - b^2 = 1.

17, p. 522... I have no idea

xiggi

"7, p. 473 has something to do with breaking the numbers down; some sort of trick that I forget how to do..."

18 sqrt 18 is the same as 18 srqrt 2*9 or 18*3 sqrt 2

The answer is thus 54 * @ or 108.

xiggi

18 on 412

Calculate (2*30*45)/(30+45) => 2700/75 equals 36.
Now I have the average speed of 36 mph for one hour of travel. Since the distance IS the same both ways (duh), the distance is 36/2 or 18 miles.

PS The formula is 2 * speed1 * speed2 / speed 1 + speed 2. I could explain the formula, but it is not necessary since the formula is easy to remember and ALWAYS works. Astute students will also notice that the formula presents a variance: multiply both speeds and divide by the straight average of the speeds given. For people who use their head before jumping to the calculator, this may allo for a quicker number manipulation. For students interested in super shorcuts, you should also know that if this type of problem appears on a MC, the answer is ALWAYS slighly below the straight average. The straight average is ALWAYS the trick question.

xiggi

18 on 657

1. To solve it you need to remember that (a-b)^2 = a^2 -2ab + b^2

2. Then, look at what was given by the ETS maniacs... You need to find a way to reduce one of the functions. The value of t=0 seems interesting because of the zero. Plug in the function for a height of 6:

6 = c-(d-0)^2 or c = 6 + (d-0)^2 or C = 6 + d^2 <= remember this one

3. Now that we have C, we can plug it in the function for 106:

106 = (6+d^2) - (d-10)^2 ... play around a bit and you'll find that d = 10.

4. Now that you have c AND d, you can simply write the function for t = 1. The answer is indeed 70.

It takes a bit of manipulation. As usual, make sure not to miss any clues. In this case, the t=0 was an important clue and not an afterthought.

xiggi

15 on 684

To find the answer, you'll have to construct or visualize two right triangles that include the midpoints.

The first one will create a hypothenuse that joins the corner below B and the point A. It is quite easy to find the value since you have two sides of 2 and 1. Now, you simple create another right triangle with a hypo that joins A and B. You have the value for the right sides as the first calculated value (it is sqrt 5) and 1.

Leave the values in root form (based on a quick look at the proposed solutions). The answer is sqrt 6.

xiggi

Post number 7 should be

The answer is thus 54 * 2 or 108 and not The answer is thus 54 * @ or 108.

devils67

Thanks for the help guys, I sure am rusty.

17 on 522

In xy plane line t passes through the origin and is perpendicular to the line 4x + y= k, where k is constant. If the two lines intersect at the point (t,t+1) what is the value of t?

optimizerdad

If lines are perpendicular, the product of their slopes is -1.

Line_2 can be rewritten as y = k - 4x, so it has a slope of -4, and Line_1 therefore has a slope of -1/-4 = 0.25
You can write Line_1 as y = n + 0.25 x, where n=0 (since the line passes through the origin). Plug in x=t, y=t+1 into this equation:

t+1 = 0 + 0.25t, from which t = (-1) / 0.75 = -4/3 .

cc_mom

I dont get how to solve this problem?
How does the x corresponde to the a?

gcf101

Look up 684 / 16 / in Consolidated List of Blue Book Math Solutions, 3rd ed.