Grade 11Algebra
if x^3 + 4x =8 find value of x^7 +64x^2
a)132
b)128
c)216
d)125
if x^3 + 4x =8 find value of x^7 +64x^2
a)132
b)128
c)216
d)125
1 Answer
Sher Mohammad
x^3 +4x=8 square the equation
x^6 +16x^2 +8x^4=64 multiply with x
x^7+16x^3+8x^5-64x=0
now x^7+64x^2 put value of x^7
64x-16x^3-8x^5+64x^2
64x-8x^2(x^3+4x)+16x^3+64x^2
64x-64x^2+16x^3+64x^2
64x+16x^3
16(x^3+4x)=16*8=128
ans is B
Sher Mohammad
faculty askiitians
Other Related Questions on algebra
How do you write “the product of 18 and q” as an algebraic expression?
How do you write “the product of 18 and q” as an algebraic expression?
algebra
Last Activity: 2 Years ago