Difference between revisions of "1963 TMTA High School Algebra I Contest Problem 11"

(Created page with "== Problem == <math>x^3+y^3</math> factored into real primes is <math>\text{(A)} \quad (x+y)(x^2+2xy+y^2) \quad \text{(B)} \quad (x+y)(x^2-2xy+y^2) \quad \text{(C)} \quad (x+...")
 
(Problem)
Line 2: Line 2:
 
<math>x^3+y^3</math> factored into real primes is
 
<math>x^3+y^3</math> factored into real primes is
  
<math>\text{(A)} \quad (x+y)(x^2+2xy+y^2) \quad \text{(B)} \quad (x+y)(x^2-2xy+y^2) \quad \text{(C)} \quad (x+y)(x^2-xy+y^2)
+
<math>\text{(A)} \quad (x+y)(x^2+2xy+y^2) \quad \text{(B)} \quad (x+y)(x^2-2xy+y^2) \quad \text{(C)} \quad (x+y)(x^2-xy+y^2)</math>
  
</math>\text{(D)} \quad (x+y)(x^2+xy+y^2) \quad \text{(E)} (x+y)(x^2-y^2)<math>
+
<math>\text{(D)} \quad (x+y)(x^2+xy+y^2) \quad \text{(E)} (x+y)(x^2-y^2)</math>
  
 
== Solution ==
 
== Solution ==
 
This is a difference of cubes, so factor using the difference of cubes formula:
 
This is a difference of cubes, so factor using the difference of cubes formula:
 
<cmath>x^3 + y^3 = (x+y)(x^2-xy+y^2.</cmath>
 
<cmath>x^3 + y^3 = (x+y)(x^2-xy+y^2.</cmath>
The answer is </math>\boxed{\text{(C)}}.$
+
The answer is <math>\boxed{\text{(C)}}.</math>
 +
 
 
== See Also ==
 
== See Also ==
 
{{Succession box
 
{{Succession box

Revision as of 23:09, 1 February 2021

Problem

$x^3+y^3$ factored into real primes is

$\text{(A)} \quad (x+y)(x^2+2xy+y^2) \quad \text{(B)} \quad (x+y)(x^2-2xy+y^2) \quad \text{(C)} \quad (x+y)(x^2-xy+y^2)$

$\text{(D)} \quad (x+y)(x^2+xy+y^2) \quad \text{(E)} (x+y)(x^2-y^2)$

Solution

This is a difference of cubes, so factor using the difference of cubes formula: \[x^3 + y^3 = (x+y)(x^2-xy+y^2.\] The answer is $\boxed{\text{(C)}}.$

See Also

1963 TMTA High School Mathematics Contests (Problems)
Preceded by
Problem 10
TMTA High School Mathematics Contest Past Problems/Solutions Followed by
Problem 12