Question

find the Pythagoras theorem of 169​

Answer 1

Step-by-step explanation:

Actually, you have:     x2+ (2x+2)(2x+2) = (x+8)(x+8)

Let's pick it up at:    x2+(2x+2)2=(x+8)2

The method of expanding the squares is like expanding two polynomials -- it's called F-O-I-L for First-Outside-Inside-Last.

                     x2 +     4x2 + 4x + 4x + 4   =  x2 + 8x + 8x + 64

Using FOIL, we get:

                                4x2  - 8x - 60 = 0             (collect all term on left by subtracting)

                                   x2  - 2x - 15 = 0            (divide everything by 4 to make life easier)

                                (x-5)(x+3) = 0             (factor or use quadratic equation)

                                 x = 5   or  x = -3             (but length of 3 doesn't make sense)

                                  x = 5

Checking (very important):

    Is  5*5 + 12*12 = 13*13    ?

          25 + 144   = 169    ?     yes!