D. first, eliminate B and C, because the highest degree in these two equation is 3, a 3-degree equation has 3 roots, not 4.
between A and D, A has the roots 0, 0, 7, and -7, all real roots.
D can be factored into (x²-49)(x²+1)=0 x²=49 or x²=-1 x=7 or -7, x=i or -i two real roots, two unreal roots
for the second equation: first, find the first term by using the formula: the nth term=the first term + (n-1)*difference you are given the 13th term and d=3.7 a13=a1+(13-1)d 1.9=a1+12*3.7 a1=-42.5
the sum of the first 13 terms is S=(a1+a13)*(13/2)=(-42.5+1.9)*6.5=-263.9
Out of the following choices given, if the liquid drips at the rate of 12 cubic inches per minute, it will take approximately 3.14 minutes for all the liquid to pass through the nozzle. The correct answer will be D.
