Question

4x^3 +35 = 21 How do I solve this equation?

Answer 1

Step-by-step explanation:

if you did not make any typos, then the equation is

4x³ + 35 = 21

well, you know how that is with solving equations : let's bring all terms with variables on one side, and all constant terms to the other side.

so, as first step we eliminate the + 35 on the left side by subtracting 35 on both sides :

4x³ = 21 - 35 = -14

next, we eliminate the multiplication factor 4 by dividing both sides by 4 :

x³ = -14/4 = -3.5

and now we pull the cubic root

$x = \sqrt[3]{ - 3.5}$

x = -1.518294486...

in contrast to square roots it is not a problem for cubic roots to have negative arguments, because a negative number to the power of 3 is again negative.

-a³ = -a×-a×-a = a²×-a = -a³

Answer 2

Answer:

-$-\sqrt[3]{\frac{7}{2}}$

Step-by-step explanation:

$4x^{3}+35=21$

$4x^{3}=21-35$

$4x^{3}=-14$

$x^{3}=-\frac{14}{4}$ → $-\frac{7}{2}$

$x=-\sqrt[3]{\frac{7}{2}}$