Answer
$49-28x+4x^2$
Note: standard form lists variables first in decreasing order of exponent, so this answer could also be written as: $4x^2-28x+49$.
Work Step by Step
$$(7-2x)^2$$ $$=(7-2x)(7-2x)$$ $$=(7\times 7)+(7\times (-2x))+(-2x\times 7)+(-2x\times (-2x))$$ $$=49-14x-14x+4x^2$$ $$=49-28x+4x^2$$
Note: standard form lists variables first in decreasing order of exponent, so this answer could also be written as: $$4x^2-28x+49$$
