razor99 4 years ago Factorize

1. razor99

81a^2-100

2. anonymous

(9a+10)(9a-10) Its difference of squares

3. razor99

yep

4. razor99

swissgirl

5. razor99

@swissgirl

6. anonymous

so you got it?

7. razor99

could u tell me the steps

8. razor99

i mean could u show it

9. anonymous

I realized that we were missing the middle term Usually the equation is in the form $$ax^2+bx+c$$ In this case the equation was in this form $$ax^2+c$$ it was missing the bx So that means its difference of squares meaning that middle term canceled out

10. razor99

oh i get it thanx pippa u are a life saver

11. anonymous

I am back should i finish off explaining or did u get it?

12. razor99

could u finish it

13. anonymous

So anyways it is in the form $$a^2-b^2=(a-b)(a+b)$$ $$81x^2-100=(9x-10)(9x+10)$$ In this case our a=9x and b=10 So $$a^2=(9x)^2=81x^2 \text{ and } b^2=(10)^2=100$$