7/8
3/10 of 7/8 means 3/10 times 7/8=21/80
1hour=60mins
60 times 21/80=1260/80=15.75
answer is 15.75 mins
This is a quadratic equation because it has degree 2.
As known as a parabola
A) Height -7 = base
B) .5 * height * base = 60
Substituting A into B
B) .5 * height * (height -7) = 60
B) .5*height^2 -3.5*height = 60
B) .5*height^2 -3.5*height -60 = 0
Using the quadratic formula:
Height = 15
Subtracting 7 gives us the base length
Base = 8
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Double-Check
.5 * 15 * 8 = 60
Answer:
x = 18
Step-by-step explanation:
Given
+ 1 = 
+ 7 ( subtract 1 from both sides )
= + 6
Multiply through by 15 to clear the fractions
9x = 4x + 90 ( subtract 4x from both sides )
5x = 90 ( divide both sides by 5 )
x = 18
