a+b+c=a+(b*.3)

Solution for a+b+c=a+(b*.3) equation:

Simplifying
a + b + c = a + (b * 0.3)

Reorder the terms for easier multiplication:
a + b + c = a + (0.3b)

Add '-1a' to each side of the equation.
a + b + -1a + c = a + -1a + (0.3b)

Reorder the terms:
a + -1a + b + c = a + -1a + (0.3b)

Combine like terms: a + -1a = 0
0 + b + c = a + -1a + (0.3b)
b + c = a + -1a + (0.3b)

Combine like terms: a + -1a = 0
b + c = 0 + (0.3b)
b + c = (0.3b)

Solving
b + c = (0.3b)

Solving for variable 'b'.

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

Add '(-0.3b)' to each side of the equation.
b + (-0.3b) + c = (0.3b) + (-0.3b)

Combine like terms: b + (-0.3b) = 0.7b
0.7b + c = (0.3b) + (-0.3b)

Combine like terms: (0.3b) + (-0.3b) = 0.0
0.7b + c = 0.0

Add '-1c' to each side of the equation.
0.7b + c + -1c = 0.0 + -1c

Combine like terms: c + -1c = 0
0.7b + 0 = 0.0 + -1c
0.7b = 0.0 + -1c
Remove the zero:
0.7b = -1c

Divide each side by '0.7'.
b = -1.428571429c

Simplifying
b = -1.428571429c