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.

529 and 531

step-by-step explanation:

15% chance.

step-by-step explanation:

3/10 times, the 5 year old will get a tablet. 5/10 times, the 13 yer old will get a tablet. multiply both fractions to get 15/100 times, both would have a tablet.