# Help with some basic algebra

• Nov 27th 2006, 11:03 AM
jimmybob
Help with some basic algebra
Need help with a few of these

Q1 Factorise this expression
bx + by +mx + my

Q2 make the symbol in brackets the subject

t = 2(pie) sq2 l
---
g

(pie) = pie symbol

sq2 = square root

Make l the subject

Q3. Same question again make the symbol in brackets the subject

p-mg = mv(sq)
------
r

Make M the subject

and (sq) is squared

Q4. Simplify the expressions

a(2) x a(3) x a(-5)

The number in brackets is the power

and square root 9a(4)b(2)

Thank you very much all!
• Nov 27th 2006, 11:15 AM
OReilly
Quote:

Originally Posted by jimmybob

Q1 Factorise this expression
bx + by +mx + my

$bx + by + mx + my = b(x + y) + m(x + y) = (x + y)(b + m)$
• Nov 27th 2006, 11:19 AM
OReilly
Quote:

Originally Posted by jimmybob

Q4. Simplify the expressions

a(2) x a(3) x a(-5)

The number in brackets is the power

and square root 9a(4)b(2)

Thank you very much all!

I think i saw this question before on this forum but I will answer it again.

$a^2 \cdot a^3 \cdot a^{ - 5} = a^5 \cdot \frac{1}{{a^5 }} = \frac{{a^5 }}{{a^5 }}1$

$\sqrt {9a^4 b^2 } = 3a^2 b$
• Nov 27th 2006, 11:24 AM
OReilly
You posted Q4 again.

Previous your post where those questions are is:
http://www.mathhelpforum.com/math-he...l-subject.html

Don't double post.
• Nov 27th 2006, 11:28 AM
OReilly
Quote:

Originally Posted by jimmybob

Q3. Same question again make the symbol in brackets the subject

p-mg = mv(sq)
------
r

Make M the subject

and (sq) is squared

Do you mean to solve equation for m?

If it is then:

$\begin{array}{l}
p - mg = \frac{{mv^2 }}{r} \\
\frac{{mv^2 }}{r} + mg = p \\
\frac{{mv^2 + rmg}}{r} = p \\
mv^2 + rmg = pr \\
m(v^2 + rg) = pr \\
m = \frac{{pr}}{{v^2 + rg}} \\
\end{array}
$