I believe #7 would be 5:13, #8 to be 6:7, #9 to be 13:18, #10 to be 18:5.
I hope this helps.
14 because a negative minus a negative is a positive; you add a line and change the sign
Let's formulate an equation first. For exponential growth, we follow the formula. b = 800, r - 0.027. Hence,
y = 800(1+0.027)^t
Then, at t = 21, y will be determined
y = 800 (1+0.027)^21
y = 1399.81 = 1400
Thus, the amount of bacteria present after 21 hours is 1400.
The answer is c because you have the right mathmatics
solution is (4, - 7 )
given the equations
y = 2x - 15 → (1)
4x + 3y = - 5 → (2)
substitute y = 2x - 15 into (2)
4x + 3(2x - 15) = - 5
4x + 6x - 45 = - 5
10x - 45 = - 5 ( add 45 to both sides )
10x = 40 ( divide both sides by 10 )
x = 4
substitute x = 4 into (1) for corresponding value of y
y = (2 × 4 ) - 15 = 8 - 15 = - 7
solution is (4, - 7 )