Option C:
is the value of a and b
Explanation:
Given that the expression 
We need to determine the value of a and b
Let us consider the term
and take the prime factorization of the term 648
Thus, we have,
648 divides by 2,

324 divides by 2,

162 divides by 2,

81 divides by 3,

27 divides by 3,

9 divides by 3,

Thus, we have,

Therefore, equating the powers of 2 and 3, we get,

Hence, the value of a and b is 3 and 4
Thus, Option C is the correct answer.
X2-1 I think that's the answer because there's 1 less, 1 take away the x and squared!! hard to explain but that's how I thought about it
3+4 = 7
so
21 / 7 3
3 x 3 = 9
3 x 4 = 12
answer
£21 in ratio 3:4 is £9:£12
Mass=Density*Volume
Density=1.1 g/cc
Volume of a cylinder: <span>π*r^2*h
</span>Radius of the top of the can: 3.57
Volume of this can: 480.47
480.47*1.1=528.517
If I'm correct the mass of this can should be 528.517