Answer:
1 seconds after being thrown, the stone reaches its max height
Step-by-step explanation:
The parabolic (quadratic) equation is:
Lets expand this in the form 
, so we have:
We can say the values of a,b, and c, now to be:
a = -5
b = 10
c = 40
The number of seconds at which the max would occur is given by the point, x, at:
We know a and b, let's find the seconds, x,
Hence,
1 seconds after being thrown, the stone reach its max height
Explanation: 3 x 2 + 10 x + 3 We can Split the Middle Term of this expression to factorise it. In this technique, if we have to factorise an expression like a x 2 + b x + c , we need to think of 2 numbers such that: N 1 ⋅ N 2 = a ⋅ c = 3 ⋅ 3 = 9 and, N 1 + N 2 = b = 10 After trying out a few numbers we get: N 1 = 9 and N 2 = 1 9 ⋅ 1 = 9 , and 9 + ( 1 ) = 10 3 x 2 + 10 x + 3 = 3 x 2 + 9 x + 1 x + 3 = 3 x ( x + 3 ) + 1 ( x + 3 ) ( 3 x + 1 ) ( x + 3 ) is the factorised form for the expression.
c
, we need to think of 2 numbers such that:
N
1
⋅
N
2
=
a
⋅
c
=
3
⋅
3
=
9
and,
N
1
+
N
2
=
b
=
10
After trying out a few numbers we get:
N
1
=
9
and
N
2
=
1
9
⋅
1
=
9
, and
9
+
(
1
)
=
10
3
x
2
+
10
x
+
3
=
3
x
2
+
9
x
+
1
x
+
3
=
3
x
(
x
+
3
)
+
1
(
x
+
3
)
(
3
x
+
1
)
(
x
+
3
)
is the factorised form for the expression.
224 hours and 43 seconds.
24
Since each trip takes half a gallon of gas, you divide the amount of gas by how much per trip.
That gives you 24 trips he can make with the gas.
