Answer:
30-2x
Step-by-step explanation:
yuson has to finish am total of 30 hours in community service
she does 2 hours each day
in x days, hour of service done=2x
after x days hours of service left=30-2x
therefore the linear equation representing the hours yuson has left after x days is:
30-2x
The Given equation is , 3 x + x = 440,
Let speed of train A is x Km/hour and Speed of train B which is a Bullet train which starts from same station but from different platform is 3 times the speed of train A.
And Sum of their Velocities is i.e Velocity of train A and Velocity of train B is 440 Km/hour.
The sum of angles for any triangle is 180°. So x=180-19-(180-51)=32°
Part A:

The first step of completing the square is writing the expression

as

which expands to

.
We have the first two terms exactly the same with the function we start with:

and

but we need to add/subtract from the last term, 49, to obtain 41.
So the second step is to subtract -8 from the expression

The function in completing the square form is

Part B:
The vertex is obtained by equating the expression in the bracket from part A to zero


It means the curve has a turning point at x = -7
This vertex is a minimum since the function will make a U-shape.
A quadratic function

can either make U-shape or ∩-shape depends on the value of the constant

that goes with

. When

is (+), the curve is U-shape. When

(-), the curve is ∩-shape
Part C:
The symmetry line of the curve will pass through the vertex, hence the symmetry line is

This function is shown in the diagram below