Question

Solve the perimeter formula for an isosceles triangle, P = 2a + b for a.

a = P + 2b



a = P – 2b

Answer 1

The solution for a is a =
`(P-b)/(2)`

Explanation:

To solve an equation for one of its variables, do that

1. Separate the term of this variable on one side and the other terms on the other sides
2. Make the coefficient of the variable equals1 (if it is not 1)

Let us solve the question

∵ The perimeter formula for an isosceles triangle is P = 2a + b

∵ We need to solve it for a

→ By using the first step above, subtract the two sides by b to move it

from the right side to the left side

∵ P - b = 2a + b - b

∴ P - b = 2a

→ By using the second step above, divide both sides by 2

∵
`(P-b)/(2)` =
`(2a)/(2)`

∴
`(P-b)/(2)` = a

→ Switch the two sides

∴ a =
`(P-b)/(2)`

∴ The solution for a is a =
`(P-b)/(2)`