The Purplemath Forums

I need to find the numbers for each letter in "THINK + RETHINK = REFLECT". They gave me that "I" stands for the number "1". Since the "RE" is the same on the second number and the answer, I really only have to have the numbers for "THINK + THINK = FLECT&q...

I know some about powers and about solving by factoring. One of my "challenge" problems is to solve 2^(2x) - 7(2^x) - 8 = 0, and the hint in the book says "Let y = 2^x". I think this gives me y^2 - 7y - 8 = 0. Is that right? Because then I'm pretty sure I can finish this. Thanks.

I don't have my book, just my homework. I want to check if I'm doing this right: Juliet was looking at Romeo from her balcony one evening. Romeo was standing at a distance of 10 m away from the foot of the house. When Juliet looked at Romeo's head, the angle of depression was 40 degrees. When she lo...

I have to find the value for (x - a)(x - b)(x - c) ... (x - z), but they didn't give me any numbers for a, b, c, ..., z. How should I start this?

How did I not see that?

A right circular, conical vessel of altitude 21 cm and base radius 11 cm is kept with its vertex downwards. If 2 litres of water is poured into it, how high above the vertex will the level of the water be? I think I need to convert the 2 L to 2000 cc's, and use similar similar triangles to find the...

A carpenter can make a cabinet in 30 hours. If he works for 21 hours at the normal rate of pay and 9 hours at the overtime rate, he will be paid $69. But if he works for 27 hours at the normal rate and 3 hours at the overtime rate, his earnings will be $63. Find his normal and overtime rates of pay...

i've been doing this stuff for a few grades now, and sometimes its easier to do it the way i learned back before i started doing variables. Thank you for showing how to do it the algebra way!

If 12 men can dig 35 holes in 14 days, (a) how many men are needed to dig 35 holes in 8 days? (b) How many days would it take 12 men to dig 30 holes? Twelve men working 14 days is (12)(14) = 168 man-days. a: If you have 8 days and need 168 man-days, then you need (168)/(8) = 21 men. b: Thirty-five ...

. . . . . \frac{20 m^9 n^2}{5 m^4 n^6} . . . . . \left( \frac{7 x^6 y^3}{5 x y^2} \right) \times \left( \frac{-3 x^2 y}{6 x^2 y^2} \right) What were the instructions for these exercises? I've done two things with this stuff: Either they give you numbers to plug in for the letters, o...