(x-7)²-2(x-7)(x+3)+(x+3)²=100

Question

(x-7)²-2(x-7)(x+3)+(x+3)²=100

Answer 1

X²-14x+49-2(x²+3x-7x-21)+x²+6x+9=100
x²-14x+49-2x²-6x+14x+42+x²+6x+9=100
-6x=100-9-42-49
-6x=0
x=0:(-6)
x=0