Tip: Go step-by-step
Let the number = x
Eight times the difference between a number and seven.. = 8(x-7)
is the same as... =
the number increased by 4.. x+4
8(x-7)=x+4
Distribute
8x-56=x+4
Subtract x from both sides
7x-56=4
Add 56 to both sides
7x=60
x=60/7
A)
A negative times a negative should be positive.
-1*(-a) should be a, not -a
Step-by-step explanation:
√7 * √7 = 7 , which is not a irrational number
<span>v = 4/3*pi*r^3
derivating both sides with respect to t
dv/dt = 4*pi*r^2*dr/dt
when d = 1.7, r = 0.85, and dv/dt = 2:
2 = 4*pi*(0.85)^2*dr/dt
thus
dr/dt = 1/(2pi*(0.85)^2)
=1/(2*3.14*0.85^2)
=0.22</span><span />