Answer:
x = 1 ±2sqrt(5)
Step-by-step explanation:
2x^2-4x-9=29
Add 9 to each each side
2x^2-4x-9+9=29+9
2x^2-4x=38
Divide by 2
2/2x^2-4/2x=38/8
x^2 -2x =19
Complete the square
x^2 -2x + (-2/2)^2 = 19 +(-2/2)^2
x^2 -2x +1 = 19+1
(x-1)^1=2 = 20
Take the square root of each side
sqrt((x-1)^2) = ±sqrt(20)
x-1 = ±sqrt(20)
Add 1 to each side
x-1+1 = 1 ±sqrt(20)
x = 1 ±sqrt(20)
Simplifying the square root of 20
x = 1 ±sqrt(4)sqrt(5)
x = 1 ±2sqrt(5)
22 centimeters is the answer
Answer for number 4 is 
hour.
Step-by-step explanation:
Maximum hour spent for all homework (English homework + math homework) is 2 hours.
Let us assume the hours spent for English homework be 'e'.
It is given that:
(Hours spent for math homework) = 2 × (Hours spent for English homework)
Hours spent for math homework = 2 × e = 2e
Total hours spent = (Hours spent for math homework) + (Hours spent for English homework)
Total hours spent = 2e + e = 3e
2 = 3e
3e = 2
∴ e =
Therefore number of hours spent on English homework is equal to hours.
Answer:
Her error was multiplying -3 and -4 which gives +12 but she wrote -12 instead
Step-by-step explanation:
Mariana workings:
-3(2x - 4) = -12
-6x - 12 = -12
Her error was multiplying -3 and -4 which gives +12 but she wrote -12 instead
-6x = 0
x=0
Correct workings:
-3(2x - 4) = -12
-6x + 12 = - 12
-6x = -12 - 12
-6x = -24
x = -24/-6
x = 4
