90 divided by 3 + ( 3 - 2 ) - 20.

11

Step-by-step explanation:

first 3-2=1 the divide 90 by 3 then add the 1 the subtract that by 20 and you will get 11

the 2 figures are congruent bc if you reflect abcd over the y axis then over the d axis the figures overlap

step-by-step explanation:

one of the most important purposes of surface treatment is to alter surface properties according to the requirement of specific applications. for example, hydrophobic coating has been utilized on windshield and eyeglasses. gold atom monolayer on substrate has become a popular surface bioconjugation strategy.