3x-6y=27 and 6x+9y=-30 solve this system of linear equations

x= 1 and y= -4

Step-by-step explanation:

3x-6y=27

3(x-2y)=27

divide both sides by 3

x-2y=9 ->eq 1

6x+9y=-30

3(2x+3y)=-30

divide both sides by 3

2x+3y=-10 ->eq 2

multiply eq 1 by 2

2x-4y=18 -> eq 3

now subtract eq 3 from eq 2

  2x + 3y= -10

 ± 2x + 4y= ±18  (-4y becomes +4y after changing sign due to subtraction)

     7y = -28

     y = -4    by dividing 7 on both sides

put value of y in eq 1

x-2(-4)=9

x+8=9

x= 9 - 8

x= 1

solution:

the given function is ,

      =

the three roots of this quadratic function is , 0 ,8 and 10.all the roots are real and rational.

if a quadratic equation is of the form ,

sum of the roots = a + b +c= 0+8+10=18=  

product of roots taken two at a time = a b + b c+ c a = 0+80+0=80 =  

product of roots = a b c = 0=  

there are 11 doors in a hall starting from 0 to 11.the entry in the hall is permitted through gate number 0 and exit is allowed through only gate number 8 and 10.so, three roots(0,8,10) of quadratic function is given by entry and exit route of this hall.

28

step-by-step explanation:

because that's the answer