Answer:
320 cu. yd.
Step-by-step explanation:
V = Bh where B is the area of the base (triangle) and h is the height of prism
B = bh/2 = 8(8)/2 = 64/2 = 32
height of prism = 10
V = 32(10) = 320 cu. yd.
Answer:
The number of months cost same is 9
Step-by-step explanation:
Given:
Equation for the first plan y = 38x + 15
Equation for the second plan y = 31x + 78.
where x is the number of month
Solution:
38x + 15 = 31x + 78
7x + 15 = 78
7x = 63
x = 9
<span>First note that y cannot equal -7 or -1 as division by zero is undefined. So that if it comes up in our solution we know that it is not a real solution.
[(y+4)/(y+7)]+1=(y+3)/(y+1) make the left side have a common denominator
(y+4+y+7)/(y+7)=(y+3)/(y+1) combine like terms on left side
(2y+11)/(y+7)=(y+3)/(y+1) cross multiply
(2y+11)(y+1)=(y+3)(y+7) expand
2y^2+13y+11=y^2+10y+21 subtract y^2 from both sides
y^2+13y+11=10y+21 subtract 10y from both sides
y^2+3y+11=21 subtract 21 from both sides
y^2+3y-10=0 expand so factoring is easier
y^2-2y+5y-10=0 factor
y(y-2)+5(y-2)=0 which is equal to
(y+5)(y-2)=0
y=-5 or 2</span>