1) 7(a+y)
2) 2x^2-14x+6
3) x^2+6x+5x+30=x^2+11x+30
4) a^2-4a+a-4=a^2-3a-4
5) 8x-6x=11+3
2x=14
x=7
6) (3x^2+12x-2x-8)-(3x+15)(x-1) = (3x^2+10x-8)-(3x^2-3x+15x-15) = 3x^2+10x-8-3x^2+3x-15x+15 = 7-2x = 0
-2x=-7
x=3,5
1) 7(a+y)
2) 2x^2-14x+6
3) x^2+6x+5x+30=x^2+11x+30
4) a^2-4a+a-4=a^2-3a-4
5) 8x-6x=11+3
2x=14
x=7
6) (3x^2+12x-2x-8)-(3x+15)(x-1) = (3x^2+10x-8)-(3x^2-3x+15x-15) = 3x^2+10x-8-3x^2+3x-15x+15 = 7-2x = 0
-2x=-7
x=3,5