MannyL
December 19, 2006, 2:29am
1
After just taking the accuplacer exam for South University online I scored a 70 in Algebra.

I was not sure how to find the correct answers for two problems so I guessed. I’m hoping someone here can explain how to do them so I understand in the future.

```
__ ______ __________
√ 45 - √ 20
_____________________________
__________
√ 5
```

That should be the square root of 45 minus the square root of 20 over the square root of 5
And

```
b + b [sup]2[/sup]
------------------------------------------------
b
```

Valgard
December 19, 2006, 2:35am
2
The general rule is that (a+b)/c = (a/c)+(b/c). Try that and see what you get.

ArmenE
December 19, 2006, 3:20am
3
The first question breaks down to:
(√45 - √20)/√5
=(√9√5 - √4 √5)/√5
=(3√5 - 2√5)/√5
= (1√5)/√5
=1

The second is:
(b+b^2)/b

```
b * (1 + b)
= -----------
b
```

(the b’s ‘cancel out’ here, meaning that b/b = 1, so you are left with:
= 1 + b

Another way of looking at this last one, using **Valgard’s ** hint, is:
(b+b^2)/b

```
b b^2
= - + ---
b b
1 b
= - + -
1 1
= 1 + b
```

You could also multiply the entire thing by √5/√5 (i.e 1, so the overall value won’t change), converting to [√5 x (√45 - √20)] / (√5 x √5)
= (√5 x √45 - √5 x √20) / 5

= (√225 - √100) / 5

= (15-10) / 5

= 5 / 5

= 1

MannyL
December 19, 2006, 4:49am
5
Ok so I got the first one wrong and the second one right.

Giles
December 19, 2006, 12:23pm
6
However,
(b+b^2)/b = 1 + b
only if b is not equal to zero. If b = 0, the expression is undefined.