ElectricPavlov

See this first

https://web2.0calc.com/questions/question_65419

then we need to modify it by multiplying by -2

(x^2 - 6x + 4 ) x (-2) = -2x^2 +12x - 8        Vertex will be at  x = - b/2a =  - 12 / (2*-2) = 3

The use this value of x to find the 'y' value by substituting into the equation   y = .........

First box  4 choices ....2 are regular pencils    2/4 = 1/2

Second box  12 choices   ... 7 are color pencils   7/12

7/12  x   1/2 =    7/24

The equation would look like this

(x - r1)(x-r2)    = x^2 - r1x - r2x + r1r2

                      = x^2 -3x-sqrt5x  - 3x+sqrt5x  +  9-5

                      = x^2 -6x + 4  

Graph #2  shows   |x-3|<4       It cannot include 7 or -1      Those would = 4 , hence the hollow endpoints

                                                                all of the nubers in between would result in <4

99km/9l =  11 km/l

12 l  x   11 km/l = 132 km     with 12 l

Yes. it is B

  As an exercise    let's find the current through the 10 ohm resistor

9v/10 ohm  =   .9 A  

so the total current is thus  .45 + .9 = 1.35 A

the resultant resistance is thus    9 v/ 1.35 A = R = 6 .667 ohm

Is this true?

     Calculate the resultant resistance of the two resistors in parallel     1/ (1/10 + 1/20)  =  6.667   ohm  !    TRUE !

Again....the resistors are wired in PARALLEL ....so they BOTH have 20v applied across them

v/r = i      9v  / 20 ohm =.......A

Circumference = pi d  = pi  2 r  =  pi (9) (2) = 18 pi

fraction of the circumference is   3 /18pi   x   2pi  = 6/18 = 1/3 R    or 19.0985^o

We already went through this !
https://web2.0calc.com/questions/let-find#r3