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If f(x) = ax + b, where a and b are real numbers. If f( f ( f(x) ) ) = 8x + 21, what is the value of a + b [DCRU]
A. 4
B. 3
C. 5
D. 2

Read Solution (Total 9)

f(f(f(x)))= (a^3)x+(a^2)b+ab+b = 8x+21
we have on comparing
a=2
b=3
a+b = 5
10 years agoHelpfull: Yes(27) No(0)

f(x)=ax+b
f(f(x))=a(ax+b)+b=a^2x+ab+b
f(f(f(x)))= a^2(ax+b)+ab+b=a^3+a^2b+ab+a=8x+21
on comparing a^3=8=>a=2
a^2b+ab+a=21=>b=3
so a+b=2+3=5
10 years agoHelpfull: Yes(10) No(1)
f(f(f(x)))=a^3x+a^2b+ab+b=8x+21...from that...a=2,b=3..a+b=5
10 years agoHelpfull: Yes(2) No(0)
5 a=2 b=3 so ans is 5
10 years agoHelpfull: Yes(0) No(1)
a+b=5
a=2, b=3
10 years agoHelpfull: Yes(0) No(0)
c..........................
10 years agoHelpfull: Yes(0) No(0)
a^3x+a^2b+ab+b=8x+21. so a=2 & b=3. a+b=5
10 years agoHelpfull: Yes(0) No(0)
f(f(f(x)))= (a^3)x+(a^2)b+ab+b = 8x+21
we have on comparing
a=2
b=3
a+b = 5
10 years agoHelpfull: Yes(0) No(0)
put 3 times f(x)value and compare with 8x + 21
and get 5
10 years agoHelpfull: Yes(0) No(0)

TCS Other Question

Maximum number of identical pieces (of same size) of a cake by making only 3 cuts? There are 5 packers A, B, C, D, and E in a company. The five packers A, B, C, D and E charge $66, $52, $46, $32, and @28, respectively, to pack each item. The time taken by the packers to pack one item is 20 minutes, 24 minutes, 30 minutes, 40 minutes and 48 minutes, respectively. All the items are sold at end of the day. Each item earns a profit of 100 dollars, and the packers are paid from this profit. If each packer works 8 hours a day, which packer contributes the most to the net profit of the company?
option
A. Packer C [DCRU]
B. Packer A
C. Packer B
D. Packer D