For the equation 21 + 3x = 3x + k, what value of k will create an equation with infinitely many solutions?

(urgent ) use pi 3.14 to estimate the circumference of the circle to the nearest hundredth middle is 4in (urgent )

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

Sundar used linear combination to solve the system of equations shown. he did so by multiplying the first equation by 5 and the second equation by another number to eliminate the y-terms. what number did sundar multiply the second equation by? 2x+9y=41 3x+5y=36