Solve 999=1/2[2*3+(n-1)3]

$$999 = \frac { 1 } { 2 } [ 2 \times 3 + ( n - 1 ) 3 ]$$

Solve for n

$$n=665$$

Steps for Solving Linear Equation

Multiply both sides by 2, the reciprocal of \frac{1}{2}.

$$999\times 2=2\times 3+\left(n-1\right)\times 3$$

Multiply 999 and 2 to get 1998.

$$1998=2\times 3+\left(n-1\right)\times 3$$

Multiply 2 and 3 to get 6.

$$1998=6+\left(n-1\right)\times 3$$

Use the distributive property to multiply n-1 by 3.

$$1998=6+3n-3$$

Subtract 3 from 6 to get 3.

$$1998=3+3n$$

Swap sides so that all variable terms are on the left hand side.

$$3+3n=1998$$

Subtract 3 from both sides.

$$3n=1998-3$$

Subtract 3 from 1998 to get 1995.

$$3n=1995$$

Divide both sides by 3.

$$n=\frac{1995}{3}$$

Divide 1995 by 3 to get 665.

$$n=665$$