The product of (a + b) and (a + b ) is

• a² + 2ab - b²

• a² - 2ab + b²

• a² + 2ab + b²

The  product of ( x + a)  and (x - b) is

• x² + (a - b)x - ab

• x² - (a - b)x - ab

• x² + (a - b)x + ab

The value of x² - 3 at x = -1  is

• -2

• -1

• -4

The value of - x² + 3 at x = -1  is

• 1

• 4

• 2

•  

Add: 9xy - 3yz + 2zx; 2xz + 9xy - 4y and -2xz + 5x + 3xy.