Answer:

Step-by-step explanation:
The first function is
.
We make y the subject of this function to obtain,
.
This is graph will open downwards because
.
At y-intercept of this graph,
.


The y-intercept is
.
At x-intercept
.


.
The x-intercepts are,

Also the vertex form of the function is,
.
Therefore the vertex of the parabola is
.
We plot all the points obtained and draw a smooth curve to obtain the curve as show in the diagram.
The second function is


This is the graph of the basic quadratic function
that has been turned upside down.
This graph also has the vertex,y-intercept and x-intercept all at
.
We now graph this too on the same graph sheet as the first one to obtain the blue graph as shown in the diagram.
These two graphs intersect at the point,
.
Therefore the correct answer is B
X=12
-5+17=12 - this is the quickest way to solve an easy equation like this
Answer:
5,6 and 9, 10 so E and F
Step-by-step explanation:
If it is question 9 of 1a
Answer:
- not possible: 1, 2, 4, 5, 8, 11
- possible: all others
Step-by-step explanation:
Obviously, all multiples of 3 and 7 can be paid.
1 cent can be added by adding a 7-cent stamp and taking away two 3-cent stamps. 2 cents can be added by adding three 3-cent stamps and taking away one 7-cent stamp. Hence any value more than 7 +2(3) = 13 cents can always be accommodated.
Amounts that are impossible:
1, 2, 4, 5, 8, 11 cents
All other positive integer amounts are possible.