Mir evaluated 5x - (x + 3)2 for x = 2, as shown. Describe Amir's mistake and find the correct answer. 5(2) - (2 + 3)2 = 10 + (-5)2 = 10 + 25 = 35

correct answer =0

Step-by-step explanation:

Step 1

5x - (x + 3)2

Putting the coefficient of x =2 in the equaton we have

5(2) - (2 + 3)2

Solving out

5(2) - (5)2

= 10- 10

=0

Step 2

Amir's mistake was in the multiplication  and wrong use of the negative sign of the bolded below

5(2) - (2 + 3)2 = 10 + (-5)2 = 10 + 25 = 35

-(5)2 cannot give 25 instead 10, so him getting a 25 and wrong use of the negative and positive made his answer wrong.

The right answer as calculated in step 1 = 0

Amir didn't follow the order of operations and is wrong. Amir should have squared 5 and then subtracted rather than distributing the negative and squaring it. The correct answer is -15

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.