21=2(4a+3)

Solution for 21=2(4a+3) equation:

Simplifying
21 = 2(4a + 3)

Reorder the terms:
21 = 2(3 + 4a)
21 = (3 * 2 + 4a * 2)
21 = (6 + 8a)

Solving
21 = 6 + 8a

Solving for variable 'a'.

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

Add '-8a' to each side of the equation.
21 + -8a = 6 + 8a + -8a

Combine like terms: 8a + -8a = 0
21 + -8a = 6 + 0
21 + -8a = 6

Add '-21' to each side of the equation.
21 + -21 + -8a = 6 + -21

Combine like terms: 21 + -21 = 0
0 + -8a = 6 + -21
-8a = 6 + -21

Combine like terms: 6 + -21 = -15
-8a = -15

Divide each side by '-8'.
a = 1.875

Simplifying
a = 1.875