# Algebra2

posted by .

Help?

1.2x^2/3+5^1/3=12

2. 6x^6/3-5x^1/3-6=0

• Algebra2 -

#1
2x^(2/3) + 5x^(1/3) = 12 , you have a typo
let x^(1/3) = y

2y^2 + 5y - 12 = 0
(2y-3)(y+4) = 0
y = 3/2 or y = -4

then x^(1/3) = 3/2 ---- x = 27/8
if x^(1/3) = -4 ----> x = -64

check:
if x = 27/8
LS = 2(27/8)^(2/3) + 5(7/8)^(1/3)
= 2(9/4) + 5(3/2)
= 9/2 + 15/2 = 12 = RS

if x = -64
LS = 2(-64)^(2/3) + 5(-64)^(1/3)
= 2(16) - 5(-4)
≠ RS

x = 27/8

(in y = x^(1/3) , x would be defined as x>0

enter 2x^(2/3)+5x^(1/3)-12 into "first graph" of
http://rechneronline.de/function-graphs/
to see what I mean. There will be only one solution at x = 27/8 )

----------

I think you have a typo in #2 if the question is supposed to be the same type
It should probably say
6x^(2/3) - 5x^(1/3) - 6 = 0

try #2 in the same way by letting y = x^(1/3)
it also factors, remember to reject a negative value of y

## Similar Questions

1. ### Algebra2

Help ? 1. x-3x^1/2+2=0
2. ### Algebra2

If f = (1, 2), (2, 3), (3, 4), (4, 5), g = (1, -2), (3, -3), (5, -5), and h = (1, 0), (2, 1), (3, 2), Help?

5/21.(-7/15)

5-(6+2).2

2x+3=7
6. ### algebra2

if a=5 and b=-3 4a-3b
7. ### algebra2

s-2/2-s-1/5=1/4
8. ### Algebra2

Help? f(x)=5 ; x=3,-2,-1,0,1,2,3
9. ### algebra2

(x-5)^1/3 -4=-2
10. ### Algebra2

2|3x-5|-8=8

More Similar Questions