Which pair of expressions are equivilent? 4x - 2 + 5x and 7x

(11 + 3x) - x and 11 + 2x

12 (x - 2) and 12x - 2

9x (4) and 13x​

a and c

step-by-step explanation:

the battle of gettysburg is considered the "high water mark" of the confederacy because it marked the greatest advance of the confederate forces against the union.

step-by-step explanation:

assume that you have 3 different side lengths.   apply the pythagorean theorem here:   square each of the two shortest sides; call them a and b, so that their squares are a² and b².   also square the longest side, calling the result c².

now, if a² + b² = c² is true, the triangle is a right triangle; otherwise it is not a right triangle.