Algebra

If a + b = 5 and (a^2) + (b^2) =13 , then ab = ?
1. 12
2. 6
3. 5
4. 13
(5+20)(−20−5) = ?
1. −425
2. 375
3. −625
4. 0
The factors of (x^2) −6x +9 are
1. (x − 3)(x − 3)
2. (x − 3)(x + 3)
3. (x + 3)(x + 3)
4. (x − 6)(x + 9)
The common factors of the algebraic expressions a(x^2)y , bx(y^2) and cxyz is
1. (x^2)y
2. x(y^2)
3. xyz
4. xy