Anonymous
Anonymous asked in Science & MathematicsMathematics · 9 years ago

# need help with some math problems.?

1. 5x /25

2. 12y^2/2y

3. 18x^2/15xy^4

4. 3x^2 - 9x /12x^2

x^2(x-8)/x(x-8)

Relevance
• I'm guessing you have to simplify the expressions?

1.| 5x /25

You get an expression that equals another one by dividing both numerator and denominator with any non-zero expression.

5 is a prime number, only divisible by 1 and 5. If you divide the numerator (5x) and denominator (25) by 1, you get the same expression. Only 5 is left... 5x/25 equals x/5

2.| 12y^2/2y

2 is divisible by 1 and by 2. So 12y^2/2y = 6y^2/y.

y^2/y equals y, so So 6y^2/y=6y

3.| 18x^2/15xy^4

15 is divisible by 1, 3 and 5. 18 is divisible by 1, 2 and 3. So we can divide numerator and denominator both by 3 and get a simpler and an equal expression: 18x^2/15xy^4=6x^2/5xy^4

x^2/x=x, so 6x^2/5xy^4=6x/5y^4

4.| 3x^2 - 9x /12x^2

If you meant (3x^2 - 9x) /12x^2 (where both 3x^2 and 9x are the numerator), than you get (3x^2 - 9x) /12x^2 equals (x-3)/4x

But if you meant what you wrote: 3x^2 - 9x /12x^2. Than you get 3x^2 - 9x /12x^2=3x^2 - 3/4x

(I hope you know why. If you don't, you ask for an explanation so you can solve it on test when it really matters.)

5.| x^2(x-8)/x(x-8)

The numerator and the denominator have the same expression (x-8) by which they are multiplied. Let's divide both by (x-8): x^2(x-8)/x(x-8)=x^2/x