The product of ( x + a) and (x - b) is
x2 + (a - b)x - ab
x2 - (a - b)x - ab
x2 + (a - b)x + ab
A.
x2 + (a - b)x - ab
Add: 9xy - 3yz + 2zx; 2xz + 9xy - 4y and -2xz + 5x + 3xy.
We write the expressions in separate rows, keeping like terms in the same column:
9xy -3yz + 2zx
+ 9xy + 2zx - 4y
+ 3xy - 2 zx + 5x
____________________________
21xy -3yz + 2zx -4y +5x
In the above example, -4y and 5x are carried over as they are, because they have no like terms. II. xz is same as zx.
The product of (a + b) and (a + b ) is
a2 + 2ab - b2
a2 - 2ab + b2
a2 + 2ab + b2
B.
a2 - 2ab + b2
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