Answer:
4.47
Step-by-step explanation:
3x²+31=91
3x²=91-31
3x²=60
x²=60÷3
x²=20
x=√20
x=4.47
31
just substitute -8 for all x
process here:
f(x) = -3x + 7
f(-8)= -3(-8) + 7
Answer:
Step-by-step explanation:
The formula for the area of a circle is : 
To work this out you would first have to work out the area of the circle. You can do this by multiplying pi by 8 squared, this gives you 201.06. This is because in order to calculate the volume you must calculate the area of one face of the shape.
The next step is to multiply 201.06 by 10, this gives you 2010.62.
1) Multiply pi by 8 squared.
2) Multiply 201.06 by 10.
Answer:
21) 12 cm
22) 5.9 cm
Step-by-step explanation:
21) The base is 10, and if the other two sides are congruent and the perimeter is 36, we can figure out with simple algebra that the sides are 13 cm long.
Half of 10 is 5, so we can use the pythagorean theorem.
5^2+x^2=13^2
Rearranging the variables we have 169-25=x^2
144=x^2
x can be plus or minus 12, but since negative length is impossible we find that x is positive 12 cm.
22) We want to use sine, because we have opposite and hypotenuse. A simple and easy way to memorize this is the SohCahToa method. If we have opposite (O) and hypotenuse (H) we have OH. Soh has the letters O and H, and the S means we should use sine.
sine 36=a/10
Plug this into a calculator or desmos scientific calculator to get a=5.9
Step-by-step explanation:
Dividing by a fraction is the same as multiplying with the opposite of the fraction. 8/9 / 3/4=8/9×4/3=32/27=1 5/27.
