Q15 is the similarity question...
so
(A1/a2)2=(l1/l2)
144/x2=99/11
99x2=1584
x2=16
x=4
Q18b) x= tan-1(78/83)? I think? :S
Q19b)
f(x)=x+1/2
g(x+1)/2= s(x+1/2)+1
=2x+2+2/2
=2x+4/2
=2(x-2)/2
=x+2
q20b) distance travelled = area under graph
= 1/2bh + lb
=1/2X10X18 + 20X18
=450
and q22c
BC = 38 0
0 38
= 38 ( 1 0
0 1)
= 38I
B X 1/38, C=I
Inverse of B is 1/38
c= 1/38( 4 6
5 -2)
B-1= (2/19 3/19
5/38 -1/19)