To find GCF, take the numbers first: 30, 110, 60. 10 goes into all these: 3*10, 11*10, 6*10. It's the greatest common factor, so remember it. Now the algebraic part: the lowest power of x is 4, so x^4 is the GCF. Combine with the number: 10x^4, the GCF: 30x^7=3x^3*10x^4, 110x^4=11*10x^4, 60x^8=6x^4*10x^4.