Help someone help me please

What are the soultion(s) to the quadratic equation 40- x^2=0

Solve the system of equations using the substitution method. {y=−3x+7x=−2y−16 enter your answers in the boxes.

There are three grizzly bears in the city zoo. yogi weighs 400.5 pounds, winnie weighs 560.35 pounds, and nyla weighs 628.29 pounds. what is the average weight of the three bears? (hint: what do they weigh all together? ) a. 502.97 pounds c. 604.38 pounds b. 529.71 pounds d. 794.57 pounds