Anyone know how to do #3 on this trig worksheet

Given the system of equations presented here: 2x + 4y = 14 4x + y = 20 which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? multiply the second equation by â’4 to get â’16x â’ 4y = â’80 multiply the second equation by â’1 to get â’4x â’ y = â’20 multiply the first equation by 2 to get 4x + 8y = 28 multiply the first equation by â’1 to get â’2x â’ 4y = â’14

Ineed asap. 35 points. in order for two polygons to be similar, two conditions must be met. first, all pairs of corresponding sides must be in proportion. second, all corresponding angles must be congruent. prove that angle congruence is not enough, by itself, to establish that two polygons are similar. do this by describing or drawing two polygons that are not similar but whose corresponding angles are all congruent.

What is the expression equivalent to (3x^2-7)