The expression $(11.98 \times 11.98+11.98 \times x+0.02 \times$ $0.02)$ will be a perfect square for $x$ equal to:
(a)0.02
(b)0.2
(c)0.04
(d)0.4
Answer
Answer (as printed): C
Explanation
Given expression $=(11.98)^{2}+(0.02)^{2}+11.98 \times x$. For the given expression to be a perfect square, we must have: $$11.98 \times x=2 \times 11.98 \times 0.02 \text { or } x=0.04 \text {. }$$
Explanation as extracted from the printed page; notation may be imperfect.