Posted by **Jonathan** on Monday, December 5, 2011 at 9:35am.

I need to use Pascal's Triangle to expand (x-1)^5

I know I use the fifth row but I'm not sure how to do it- I have a bunch of these and I'm really confused- Please help if you can-

- Algebra -
**Reiny**, Monday, December 5, 2011 at 10:31am
you know the expansion must look like

?x^5(-1)^0 + ?x^4(-1)^1 + ?x^3(-1)^2 + ?x^2(-1)^3 + ?x^1(-1)^4 + ?x^0(-1)^5

= ?x^5 - ?x^4 + ?x^3 - ?x^2 + ?x - ?

now the 5th row of the triangle has values:

1 5 10 10 5 1

put these in where the ?'s are and you are done

= x^5 - 5x^4 + 10x^3 - 10x^2 + 5x - 1

suppose you had

(x+2)^4

= **1**x^4 + **4**x^3(2) + **6**x^2(2^2) + **4**x(2^3) + **1**2^4

= x^4 + 8x^3 + 24x^2 + 32x + 16

- Algebra -
**Reiny**, Monday, December 5, 2011 at 10:33am
That last term in the 2nd last row of course is 1(2^4) or 16

## Answer This Question

## Related Questions

- Grade 9 Algebra Question 3 (LAST) - PASCALâ€™S TRIANGLE For Exercises 5 and 6, use...
- Math - Is this true or false? To expand the binomial (x2 + 3)6, use the row of ...
- algebra - 1)Use Pascal's triangle to expand (w-x)^5 2)Use the binomial theorem ...
- Precalc - 1) expand (1+3x)^4 using the Binomial Theorem. 2) Use Pascal's ...
- precalculus - use pascal's triangle to expand the expression (2x-3y)^3
- Math - Use Pascal's triangle to expand (a+b)^6 and hence find the binomial ...
- pre-cal - Use Pascal's triangle to expand the expression. (x − y)5 so I ...
- math - The numbers 1, 7, 21, 35, 35, 21, 7, 1 form a row of pascal's Triangle. ...
- MAths - What is the sum of all numbers that occur an odd number of times in rows...
- Geometry/Algebra - The segments formed by the altitude to the hypotenuse of a ...

More Related Questions