Answer:
The car must have a speed of 25 kilometres per hour to stop after moving 7 metres.
Step-by-step explanation:
Let be 
, where 
is the stopping distance measured in metres and 
is the speed measured in kilometres per hour. The second-order polynomial is drawn with the help of a graphing tool and whose outcome is presented below as attachment.
The procedure to find the speed related to the given stopping distance is described below:
1) Construct the graph of 
.
2) Add the function 
.
3) The point of intersection between both curves contains the speed related to given stopping distance.
In consequence, the car must have a speed of 25 kilometres per hour to stop after moving 7 metres.
Ok, first group x terms
f(x)=(x²+4x)-8
factor out quadratic coefient (no need but that's the step)
f(x)=1(x²+4x)-8
take 1/2 of the linear coefient and square it
4/2=2, (2)²=4
add positive and negative of it insides the parenthasees
f(x)=1(x²+4x+4-4)-8
factor perfect square
f(x)=1((x+2)²-4)-8
distribute
f(x)=1(x+2)²-4-8
f(x)=1(x+2)²-12
and, now if we wanted to find the x intercepts where f(x)=0 then
0=1(x+2)²-12
12=(x+2)²
+/-2√3=x+2
-2+/-2√3=x
x=-2+2√3 or -2-2√3
that is where the x intercept are
and completed square form is
f(x)=(x+2)²-12
Answer:
-3/8
Step-by-step explanation:
First rewrite -2 2/3 as an improper fraction: -8/3
Now invert this result: -3/8
This is the reciprocal of -2 2/3.
