Use the substitution method to solve this system.
y = 2x + 4
3x + y = 9
x = -1
y = 6
x = 6
y = -1
x = 6
y = 1
x = 1
y = 6

The result is , the last option.

Step-by-step explanation:

We have the following system:

The substitution method is a method in which we choose one equation, write one variable in function of the other, and then replace it in the second equation to find one variable. Then, with the result, you go back to the first equation, and find the other variable.

Solution:

In 1), we already have y as a function of x. So, i am going to replace this in equation 2), so we can find x.

Now that we have the value of x, i am going back to equation 1) to find the value of y

The result is , the last option.

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.