What is the sum of -2 and -18

The perimeter of a triangle is 69 cm. the first is 5 cm shorter than the second side. the third side is twice as long the first side. find the length of each side

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

Ab and bc form a right angle at point b. if a= (-3,-1) and b= (4,4) what is the equation of bc?