What substitution should be used to rewrite 4x4 – 21x2 + 20 = 0 as a quadratic equation?

We can substitute t = x² to make the given equation quadratic.

Step-by-step explanation:

The given equation is,

This is a polynomial equation of degree 4.

The standard form of a quadratic equation is,

The given equation can be written as,

Substitute   x² = t,

This a quadratic equation because the degree of the equation is 2.

only 10/60 isn't equivalent

hope this : )

a28=58

step-by-step explanation:

a1=a1+(n-1)d

a28= 4+ (28-1)2

a28=4+(27)(2)

a28=4+54

a28=58