8+4z*3.25z-1=21

Solution for 8+4z*3.25z-1=21 equation:

Simplifying
8 + 4z * 3.25z + -1 = 21

Reorder the terms for easier multiplication:
8 + 4 * 3.25z * z + -1 = 21

Multiply 4 * 3.25
8 + 13z * z + -1 = 21

Multiply z * z
8 + 13z2 + -1 = 21

Reorder the terms:
8 + -1 + 13z2 = 21

Combine like terms: 8 + -1 = 7
7 + 13z2 = 21

Solving
7 + 13z2 = 21

Solving for variable 'z'.

Move all terms containing z to the left, all other terms to the right.

Add '-7' to each side of the equation.
7 + -7 + 13z2 = 21 + -7

Combine like terms: 7 + -7 = 0
0 + 13z2 = 21 + -7
13z2 = 21 + -7

Combine like terms: 21 + -7 = 14
13z2 = 14

Divide each side by '13'.
z2 = 1.076923077

Simplifying
z2 = 1.076923077

Take the square root of each side:
z = {-1.037749043, 1.037749043}