Question

What are the solutions to the equation x2 + 3 = 124?   A. –3 and 3   B. –11 and 11   C. The equation has no solutions.   D. –10 and 10

Answer 1

$x^2 + 3 = 124 \ \ |-124\\ \\x^2+3-124 = 124 -124 \\ \\ x^2-121 =0\\ \\x^2-11^2=0 \\ \\ (x-11)(x+11)=0\\ \\x-11=0 \ \ or \ \ x+11 =0\\ \\x=11 \ \ or \ \ x=-11 \\ \\Answer : B. \ \ -11 \ and \ \ 11 \\ \\ \\ a^2-b^2=(a-b)(a+b)$