I need help answer all of them plz

Step-by-step explanation:

1a. 25/50 =x/100                

25*100= 2500/50= 50

A= 50%

1b. 35/40 = x/100

35*100= 3500/40= 87.5

A=87.5%

2a. 15/20= x/100

20*5= 100; 15*5= 75

A=75%

2b. 25/70= x/100

25*100= 2500/70= 35.71

A=35.71

3a. 15/80= x/100

15*100= 1500/80=18.75

A=18.75%

3b. 30/60= x/100

30/60= 1/2;1/2=0.5;0.5= 50%

A=50%

4a. 70/80 =x/100

70*100=7000/80 =87.5

A=87.5

4b.30/60 = 50% ( same as question #3b)

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this

(x, y)→(x − 8, y − 7)

step-by-step explanation:

enjoy!