Calculează 4xa-b:3+5xc+d:6,știind că: a=(9000-75:5-8905):4
b=76x8x(2986-2986)-575
c=3000-(48x7-85:5)-2669
d=76:4+45x4+9:9-164 pl va rog ajutatima nu prea știu va dauplsss​

Find the total area for the regular pyramid ( follow the answer set up in the picture)

Solve the given system of equations. 2y= -x+9 , 3x-6= -15

Seymour is twice as old as cassandra. if 16 is added to cassandra’s age and 16 is subtracted from seymour’s age, their ages become equal. what are their present ages? show !