Can someone please help

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39

Plz 20 points polynomials 1: subtract and simplify (–y^2 – 4y – 8) – (–4y^2 – 6y + 3) 2: multiply and simplify 2x^2 y^3 z^2 · 4xy^4 x^2 3: multiply and simplify (x – 4) (x2 – 5x – 6)

Find the radius of a circle that has a circumference of 16. the formula for the circumference of a circle is c = 2tr, where r is the radius and c is the circumference. the equation solved for r is r = c over 2π. r=4 r= 8 r=12 r= 16