1. Solving Radical Equations

Hi,

I can't solve this radical equation, can someone help?

8³√x+3 =11

Incase someone has a hard time reading that, because I know, sometimes I do, it says eight, cube root, x+3=11. The x+3 is inside the cube root, but the 11 is not.

x=4, but I don't know how the person who told me got it.

Thanks-
Isabel

2. Originally Posted by stmsnyder1
I can't solve this radical equation, can someone help?

8³√x+3 =11
So the equation, in text form, is 8*cbrt[x + 3] = 11 or, in LaTeX formatting:

. . . . . $8\,\sqrt[3]{x\, +\, 3}\, =\, 11$

A good first step in solving this radical equation would be to get the radical by itself, so start by dividing through by 8.

Then cube both sides to get:

. . . . . $x\, +\, 3\, =\, \frac{1331}{512}$

Subtract the 3 to the right-hand side, and simplify.

By the way, whoever told you that the solution is "x = 4" was mistaken. That's why, when you plugged "4" in for "x" on the left-hand side, you did not get a value of 11.