if x be the real number such that x3+4x=8,then value of the expression x7+64x2 is......
rahul
11 Years agoGrade 11
1 Answer
SHAIK AASIF AHAMED
Approved Tutor Answer11 Years ago
Hello student, For any integer n,the given equation impliesxn+3=-4xn+1+8xn so we can write such power of x in terms of lower powers. carrying out this process iteratively gives x7=-4x5+8x4 =8x4+16x3-32x2 =16x3-64x2+64x =-64x2+128 so x7+64x2=128 Hence the answer is 128