Expert: Richard J. Raridon - 6/29/2004

Question
Can you show me how to do some of these problems? If not, can you just tell me the answers and I'll try to figure out how to get there? Thank you.

1. (under a rad sign)x²-9 =(not under a rad sign)x-1

2. a³ + a² + a - 1 = 0

3. x³ + 7x - 60x = 0

4. y² - 4y = 21

5. (5a²/c)³ * (2cd/a³) = ______

...and don't worry, i've done the majority of the other problems that i knew how to do so I'm not asking you to do all of them or anything

Answer
1. (x^2-9)^1/2 = x-1
square both sides to get x^2-9 = x^2-2x+1 so x = 5
2. write it as f(a) = a^3 +a^2 +a -1
put in values for a and solve for f(a).  If a is a solution, f(a) = 0
f(1/2) is close to a solution since f(1/2) = -1/8
try a = 3/8 and a = 5/8
3. If you wrote it right, x = 0, +/- (67)^1/2
4. y^2 -4y -21 = (y-7)(y+3) so y = 7, -3
5. 250a^3d/c^2