How do I solve this I don't understand?

1.) 2x + y = 3 2.) x - 2y = -1 if equation 1 is multiplied by 2 and then the equations are added, the result is a.3x = 2 b.3x = 5 c.5x = 5

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

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.