Question

6. 7^x-1 - 40. 7^x-2=98

Answer 1

Answer:

Step-by-step explanation:

STEP

1

:

Equation at the end of step 1

 2 • (x - 3)2 -  98  = 0  

STEP

2

:

2.1     Evaluate :  (x-3)2   =    x2-6x+9  

STEP

3

:

Pulling out like terms

3.1     Pull out like factors :

  2x2 - 12x - 80  =   2 • (x2 - 6x - 40)  

Trying to factor by splitting the middle term

3.2     Factoring  x2 - 6x - 40  

The first term is,  x2  its coefficient is  1 .

The middle term is,  -6x  its coefficient is  -6 .

The last term, "the constant", is  -40  

Step-1 : Multiply the coefficient of the first term by the constant   1 • -40 = -40  

Step-2 : Find two factors of  -40  whose sum equals the coefficient of the middle term, which is   -6 .

     -40    +    1    =    -39  

     -20    +    2    =    -18  

     -10    +    4    =    -6    That's it