Answer:

Step-by-step explanation:
we have

Solve the quadratic equation to find the zero's or x-intercepts
Remember that
The x-intercepts are the values of x when the value of y is equal to zero ( water balloon reach the ground)
we know that
The formula to solve a quadratic equation of the form
is equal to
in this problem we have
so
substitute in the formula
therefore
the solution is 
Your least common denominator is 12, because
4: 4, 8, 12
6: 6, 12
Found it!
Discussion
1. Put brackets around the first two terms
y = (-x^2 + 6x) + 5
2. Take out the common factor of -1
y = -(x^2 - 6x) + 5
3. Inside the brackets, take 1/2 of - 6 and square it
y = -(x^2 - 6x + ( - 6 / 2)^2 ) + 5
y = -(x^2 - 6x + (- 3)^2 ) ) + 5
y = -(x^2 - 6x + 9 ) + 5
Note: Step 3 is very long. Make sure you work your way through it
4. You have added 9 inside the brackets. <em><u>It is actually - 9. So add 9 outside to balance the equation out. </u></em> This is the key step. Make sure you understand it.
y = - (x^2 - 6x + 9) + 5 + 9
5. Express the brackets as a square.
y = - (x + 3)^2 + 14
Discussion
The equation is now in vertex form. The minus tells you that the equation is a maximum. The maximum is located at ( - 3, 14 )
A graph follows to show the results.
Answer:
7.7 square metres or 7.669 square metres of metal sheet
Step-by-step explanation:
Volume of cylinder = 2×22/7×r×100cm
15.4 litres = 15,400 cm cube
Radius = 15 400×7/22 × 50
= 98cm
Surface area of cylinder = (2×22/7×49^2) + (2×22/7×49 × 100)
= 15 092 + 61 600
= 76 692 square cm
= 7.669 square metres of metal sheet required