Answer:
first we get y on one side by itself.
4x+5y=5
we'll move x to the other side.
4x-4x+5y=5-4x
simplify.
5y=5-4x
now we get rid of the coefficient on y.
5y/5=(5-4x)/5
simplify.
y=5/5-4x/5
y=1- 
The answer is 
Answer:
$1,080
Step-by-step explanation:
To solve, we can make a proportion
14 lessons are $210 and 72 lessons are $x
14/210=72/x
Cross multiply
14*x=210*72
14x=15120
To solve for x, we need to get x by itself. Since x is being multiplied by 14, divide both sides by 14.
14x/14=15120/14
x=1080
So, 72 lessons will cost $1,080
A(squared)+B(squared)=C(squared)
Surface area of box=1200 cm²
<span>Volume of box=s²h </span>
<span>s = side of square base </span>
<span>h = height of box </span>
<span>S.A. = s² + 4sh </span>
<span>S.A. = surface area or 1200 cm², s²
= the square base, and 4sh = the four 'walls' of the box. </span>
<span>1200 = s² + 4sh </span>
<span>1200 - s² = 4sh </span>
<span>(1200 - s²)/(4s) = h </span>
<span>v(s) = s²((1200 - s²)/(4s)) </span>
<span>v(s) = s(1200 - s²)/4 . </span>
<span>v(s) = 300s - (1/4)s^3</span>
by derivating
<span>v'(s) = 300 - (3/4)s² </span>
<span>0 = 300 - (3/4)s² </span>
<span>-300 = (-3/4)s² </span>
<span>400 = s² </span>
<span>s = -20 and 20. </span>
again derivating
<span>v"(s) = -(3/2)s </span>
<span>v"(-20) = -(3/2)(-20) </span>
<span>v"(-20) = 30 </span>
<span>v"(20) = -(3/2)(20) </span>
<span>v"(20) = -30 </span>
<span>v(s) = 300s - (1/4)s^3 </span>
<span>v(s) = 300(20) - (1/4)(20)^3 </span>
<span>v(s) = 6000 - (1/4)(8000) </span>
<span>v = 6000 - 2000
v=4000</span>
20/5 and -20/-5 are equivalent
