Answer:
a) ( r+ s) (x) = 3 x + 9
b) ( r . s ) (x) = 2 x² + 13 x +20
c) ( r- s) (x) = -1 -x
Step-by-step explanation:
Step(i):-
Given that r(x) = x +4 and s(x) = 2x + 5
a) ( r+ s) (x) = r(x) + s(x)
= x +4 + 2x +5
= 3 x + 9
( r+ s) (x) = 3 x + 9
b)
( r . s ) (x) = r(x) . s(x)
= (x+4) . ( 2x +5)
= x ( 2x +5) + 4( 2x +5)
= 2 x² + 5 x + 8 x +20
= 2 x² + 13 x +20
( r . s ) (x) = 2 x² + 13 x +20
c)
( r- s) (x) = r(x) - s(x)
= (x+4 - ( 2x +5)
= x +4 - 2x -5
= -x -1
( r- s) (x) = -1 -x
