4 x^2 + 20 x + 25 = 7
Divide both sides by 4:
x^2 + 5 x + 25/4 = 7/4
Write the left-hand side as a square:
(x + 5/2)^2 = 7/4
Take the square root of both sides:
x + 5/2 = sqrt(7)/2 or x + 5/2 = -sqrt(7)/2
Subtract 5/2 from both sides:
x = sqrt(7)/2 - 5/2 or x + 5/2 = -sqrt(7)/2
Subtract 5/2 from both sides:
Answer: x = sqrt(7)/2 - 5/2 or x = -5/2 - sqrt(7)/2
Answer:
D.
Step-by-step explanation:

10)
variable : cost of 1 square foot flooring = x
equation :
60x + 80 = 287
60x = 287 - 80
x = (287-80) / 60
11)
variable : doughnut cost = d
equation :
3(1.25) + 6d = 6.90
3.75 + 6d = 6.90
6d = 6.90 - 3.75
d = (6.90 - 3.75) / 6
12)
variable : smaller number = x
equation :
x + x + 1 = -29
2x + 1 = -29
2x = -29 - 1
x = (-29 - 1) / 2
13)
variable : number of shrubs : n
eqution :
n(25) + 110 = 260
25n = 260 - 110
n = (260 - 110) / 25
Https://www.algebra.com/cgi-bin/plot-formula.mpl?expression=highlight%28x%3C=45%29
Thing I no this one I just forgot