Chin made an error in his chart showing the multiplication of the binomial by the trinomial (3x+y)(x^2+2y+4) which change can be made to correct the chart?

(a.) the expression 3x^3 should be 3x^2
(b.) the expression 6x should be 6xy
(c.) the expression x^2y should be x^2y^2
(d.) the expression 4y should be 4y^2

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?

How do i do this? i don’t understand

Identify the number as a rational or irrational.explain. 127