3. A=bh/2
2A=bh
h=2A/b.
8. Dy-Cx=E
Dy=E+Cx
y=(E+Cx)/D
139 is suppose to be 140 and 18 is suppose to be 20, 140 x 20 = 2800
Home this works
This equation uses two properties of logarithms:


So you could take the ln from left and right hand side in the equation, and get:
(2-x)ln 3 = x ln 5
then
2 ln 3 - x ln 3 - x ln 5 = 0 =>
x(ln 3 + ln 5) = 2 ln 3
so x = 2 ln 3 / (ln3 + ln5)
Now using the 1st property you can say 2 ln 3 is ln 3² = ln9
and using the 2nd property you can say ln3 + ln5 = ln15
so x= ln9 / ln15
12.25x + 8.75y > = 90 (thats greater then or equal) <== ur inequality