Answer:
Step-by-step explanation:
1 ) k²-8k = 0
k(k-8)=0
k = 0 or k=8
2) a²+5a=0
a(a+5) = 0
a=0 or a = - 5
3 ) 6n²+5n-25=0
delta = b²-4ac b =5 and a = 6 and c= - 25
delta = 5²-4(6)(-25) = 625 = 25²
n 1 = (-5+25)/12 = 20/12 = 5/3
n 2 = (-5-25)/12 = - 30/12 = -5/2
same method for 4) and 5)