if x is a real number such that + 4x = 8 , then find the value of X+ 64x²

Asked by yeeshuraj3 | 19th Sep, 2016, 07:16: AM

Expert Answer:

x cubed plus 4 x equals 8
x cubed equals negative 4 x plus 8
For space straight n greater or equal than 0
straight x to the power of straight n plus 3 end exponent equals negative 4 straight x to the power of straight n plus 1 end exponent plus 8 straight x to the power of straight n


therefore straight x to the power of 7 space equals space minus 4 straight x to the power of 5 plus 8 straight x to the power of 4
therefore straight x to the power of 7 space equals space minus 4 left square bracket negative 4 straight x cubed plus 8 straight x squared right square bracket plus 8 open square brackets negative 4 straight x squared plus 8 straight x close square brackets
therefore straight x to the power of 7 equals 16 straight x cubed minus 32 straight x squared minus 32 straight x squared plus 64 straight x
therefore straight x to the power of 7 equals 16 straight x cubed minus 64 straight x squared plus 64 straight x
therefore straight x to the power of 7 plus 64 straight x squared space equals space 16 straight x cubed plus 64 straight x
therefore straight x to the power of 7 plus 64 straight x squared space equals space 16 open parentheses straight x cubed plus 4 straight x close parentheses
therefore straight x to the power of 7 plus 64 straight x squared space equals space 16 cross times 8 equals 128

Answered by Vijaykumar Wani | 20th Sep, 2016, 11:48: AM

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