I will go about solving this using the elimination method.
First, convert the equations.
10x + y = -20
4x + y = -12
Second, find the easiest variable to get rid of and get rid of it! (In this case, y) We will subtract to get rid of y.
6x = -8
Third, you want to solve the equation.
6x = -8 (divide by 6)
x =

Fourth, solve for y by inserting the answer for x into one of the equations.
10(

) + y = -20

+ y = -20 (subtract

)
y =

The solution for this system of equations is (

,

).
Answer:
Step-by-step explanation:
Answer:
B.Obtuse
as shown in the pictures that you put the angel is obtuse
Area of the square base = 5^2 = 25 cm^2
Area of one of the triangular side = 1/2 * 5 * 8 = 20 cm^2 and there are 4 sides
So the surface area of while pyramid = 4 * 20 + 25 = 105 cm^2
Volume of the cone = (1/3) pi r^2 h
= (1/3) pi * 5^2 * 8
= 209.44 ft^2