Answer:

Step-by-step explanation:
x² = 19x + 12
⇔ x² - 19x - 12 = 0
Calculating the discriminant :
b² - 4ac = (-19)² - 4×1×(-12) = 409
The discriminant is positive ,then the equation has two solutions.

Finding the perimetre: 7x+4x-3+x=12x-3
Good luck!
Answer:
Step-by-step explanation:
) Nth term = F + (N - 1) x D, where F=First term, N=Number of terms, D=Common difference
6th row = 23 + (6 - 1) x -3
= 23 + (5) x -3
= 23 + (-15)
= 8 - number of boxes in the top row.
b) Sum = N/2[2F + (N - 1) x D]
= 6/2[2*23 + (6 - 1) x -3]
= 3 [46 + (5) x -3 ]
= 3 [46 + -15 ]
= 3 [ 31 ]
= 93 - total number of boxes in the entire display.
Answer:
B: 6.0
Step-by-step explanation:
-3t^2+9t+54 = 0
This is the equation that needs to be solved
Divide both sides by -3
t^2 - 3t - 18 = 0
The factors of 18 are: (1 18) (2 9) (3 6)
3 - 6 = -3 and 3 x -6 = -18
So: (t + 3) (t - 6) = 0
t = -3, 6
It can't be negative so the answer is 6
Answer: 8 2/5
21/4 divided by 5/8 = 21/4 x 8/5 = 8 2/5