Find all solutions to the non-linear systems: 4#sqrtx# + #sqrty# = 34 and #sqrtx# + 4#sqrty# = 16 ?

2 Answers
Dec 5, 2017

x=64
y=4

Explanation:

if
#sqrt(x)=a#
#sqrt(y)=b#
then
#4a+b=34#
#a+4b=16#
multyply the first equation by -1; the second by 4 and add them together. Then you get

#15b = 64-34#
#b=30/15=2#
Now. Let's go back to find a.
4a+b=34 so after substitating b=2 you get:
#a=32/4=8#

then back:
#sqrt(x)=a#
#sqrt(x)=8#
#x=8^2=64#

#sqrt(y)=b#
#sqrt(y)=2#
#y=2^2=4#

the answers are #:.x=64 and y=4#

Explanation:

the equations are #4sqrtx+sqrty=34->(1)#
#sqrtx+4sqrty=16->(2)#
multiplying #(2) by -4# we get
#-4sqrtx-16sqrty=-64->(3)#
solving #(2) + (3)#
#4sqrtx+sqrty-4sqrtx-16sqrty=-64+34rArr-15sqrty=-30rArrsqrty=2rArry=4#
put #y=4# in #(1)# we get #4sqrtx+2=34rArr4sqrtx=32rArrsqrtx=8rArrx=64#