Find the volume for the regular pyramid. 4cu units, 6 cu units, or 12 cu units

Show me how you find x and determine what x is you i appreciate it : )

3x + 4y = 5 x- 3y = -7 solve by substitution

As a self-employed seamstress, you know that it takes 7 yards of material to make 3 jackets. you bought 15 yards of material to make 7 jackets. did you buy enough material? if not, how much were you over or under?