If x + y = a and x - y = b, then x =

A.) 1/2(a + b)

B.) a + b

C.) a - b

D.) 1/2ab

E.) 1/2(a - b)

A.) 1/2(a + b)

B.) a + b

C.) a - b

D.) 1/2ab

E.) 1/2(a - b)

Solve the two equations simultaneously for x, using the addition method (elimination).

x + y = a

x - y = b

-----------

2x = a + b {added the two equations together}

(a + b)

--------- = x {divided both sides by 2}

2

x = 1/2(a + b) {dividing by 2 is the same as multiplying by 1/2}

A.) 1/2(a + b) <--- answer

*- Algebra House*