if c(x)=4x-2 and d(x)=x2+5x what is (cd)(x)?A.4x3+18x2-10x,B.x2+9x-2,C.16x2+4x-6,D.4x2+20x-2
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Let us first talk about the mapping of the equations
The mapping of a function should be done mostly when the function is one-one
Else either you lose some of the solutions or end about getting two or more solutions for the same input value (When we find inverse)
now in the above question since no such mapping is asked about we can find the solution of it directly
c(x)=4x-2
d(x)=x²+5x
So
c(d(x))= 4(x²+5x)-2
=4x²+20x-2
cd(x)=4x²+20x-2
So option (D) is the correct choice
Also note there is a huge difference between cd(x) and dc(x)
The mapping of a function should be done mostly when the function is one-one
Else either you lose some of the solutions or end about getting two or more solutions for the same input value (When we find inverse)
now in the above question since no such mapping is asked about we can find the solution of it directly
c(x)=4x-2
d(x)=x²+5x
So
c(d(x))= 4(x²+5x)-2
=4x²+20x-2
cd(x)=4x²+20x-2
So option (D) is the correct choice
Also note there is a huge difference between cd(x) and dc(x)
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