I have ten mins pls help Which equation combines with the given equation to form a system of equations with the solution x = 3 and y = 9? x + 2y = 21

A.
4x + 6y = 64
B.
2x + y = 36
C.
4x + y = 21
D.
-3x + 4y = 33
E.
3x + 2y = 28

State if the two triangles are congruent. if they are, state how you know?

Astudent draws two parabolas on graph paper. both parabolas cross the x-axis at (-4, 0) and (6,0). the y-intercept of thefirst parabola is (0, –12). the y-intercept of the second parabola is (0-24). what is the positive difference between the avalues for the two functions that describe the parabolas? write your answer as a decimal rounded to the nearest tenth.

Acircle has a circumference of 7.850 units. what is its radius?