perplexus.info :: Just Math : Think twice

Think twice (Posted on 2016-09-12)

Solve for integer x:
x^1/2+x^1/4= 20

Submitted by Ady TZIDON

Rating: 5.0000 (1 votes)

Solution: (Hide)

2 answers: x1=256, x2=625
Solution: let t^4=x, then t^2+t-20=0
(t-4)*(t+5)=0
t=4, x=256; t=-5, x=625

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
Answers	Math Man	2016-09-16 16:40:23
re: Algebraic solution. Spoiler	Ady TZIDON	2016-09-15 22:52:06
Algebraic solution	JayDeeKay	2016-09-15 12:32:28
The apparent solution	Charlie	2016-09-12 10:33:10

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