Answer:
C x = (-5+sqrt(-3))/2
D x = ( -5-sqrt(-3))/2
Step-by-step explanation:
Set the polynomial equal to zero
x^2 + 5x+7 =0
Subtract 7 from each side
x^2 + 5x+7-7 =-7
x^2 + 5x = -7
Complete the square by taking the coefficient of x and dividing by 2 and then squaring it
(5/2)^2 = 25/4
x^2 + 5x + 25/4 = -7+25/4
(x+5/2)^2 = -28/4 +25/4
(x+5/2)^2 = -3/4
Take the square root of each side
x+5/2 = ±sqrt(-3/4)
Subtract 5/2 from each side
x+5/2 -5/2 = -5/2±sqrt(-3/4)
x = -5/2±sqrt(-3/4)
x = -5/2±sqrt(-3)/2
x = (-5±sqrt(-3))/2
Answer:
$130.718
Step-by-step explanation:
200/1.53= $130.718
Let 11x + 15y + 23 = 0 be equation (1)
And 7x - 2y - 20 = 0 be equation (2)
Multiply equation (1) by 2:
22x + 30y + 46 = 0
Multiply equation (2) by 15:
105x - 30y - 300 = 0
Add equations (1) and (2):
22x + 105x + 30y - 30y + 46 - 300 = 0
127x - 254 = 0
127x = 254
x = 254/127
[x = 2]
Substitute x = 2 in equation (1) to find y:
11(2) + 15y + 23 = 0
22 + 15y + 23 = 0
15y + 45 = 0
15y = -45
y = -45/15
y = -3
Therefore, x = 2 and y = -3.
Answer:31/73*100
=42%
Step-by-step explanation:
Answer:
22.5
Step-by-step explanation:
25-2.50=22.4