If the GCD for the following $64x^8,240x^6$ is $k{x}^m$, find the value of $k+m$

Find the GCD for the following:

$64x^8, 240x^6$

Find the GCD for the following:

$a{b}^2{c}^3,a^2{b}^{3}c,a^{3}b{c}^2$

Find the GCD for the following: $35x^5{y}^3{z}^4,49x^{2}y{z}^3,14x{y}^2{z}^2$

Find the GCD for the following: $25a{b}^{3}c,100a^{2}bc,125ab$

Find the GCD for the following:

$3abc, 5xyz, 7pqr$

Find the GCD of the following:

$(2x+5),(5x+2)$

Find the GCD of the following:

$a^{m+1},a^{m+2},a^{m+3}$

Find the GCD of the following:

$2a^2+a,4a^2-1$