I have This too sooo hard
When a quadratic equation ax^2+bx+c has a double root, the discriminant,
D=b^2-4ac=0
Here
a=2,
b=b,
c=18
and
D=b^2-4ac=b^2-4*2*18=0
solve for b
b^2-144=0
=> b= ± sqrt(144)= ± 12
So in order that the given equation has double roots, the possible values of b are ± 12.
Answer: 22
Step-by-step explanation:
I got it right on khan academy
10d+ 25q+5n= 805
D= n+8
Q= n+ 5
10d+ 25q+5n= 805
10(n+8)+25(n+5)+5n=805
10n+80+25n+125+5n=805
40n+205=805
40n=805-205
40n= 600
N=600/40
N= 15
D= n+8
D= 15+8
D= 23
Q=n+5
Q=15+5
Q=20
So 15 nickels ,23 dimes and 20quarters .
To check
15(0.05)= $0.75
23(0.10)=$2.30
20(0.25)=$5.00
Add it
5.00+2.30+0.75=8.05
7.30+.75=8.05
8.05=8.05
