Answer
(a)
i.
121
ii.
132
iii.
143
(b)
They are the same when x is replaced by 10.
Work Step by Step
(a)
i.
(x+1)(x+1)=$x^{2}$+2x+1
$11\times11$=(10+1)(10+1)=$10^{2}$+2(10)+1=121
ii.
(x+1)(x+2)=$x^{2}$+3x+2
$11\times12$=(10+1)(10+2)=$10^{2}$+3(10)+2=132
iii.
(x+1)(x+3)=$x^{2}$+4x+3
$11\times13$=(10+1)(10+3)=$10^{2}$+4(10)+3=143
(b)
x is replaced by 10 each time so the process is the same
