Answer:
b = 3 and a = -1
Step-by-step explanation:
You have your given equation:
2a - 3b = -11
a + 3b = 8
You need to find what a and b is.
To find b:
2a - 3b = -11
-2a - 6b = -16
I multiplied a + 3b = 8 by -2. When you multiply a number you have to multiply all of them. You have to choose a number that would cancel out all of a.
So now your equation would look like this when you solve for b:
2a - 3b = -11
-2a - 6b = -16
-------------------
a - 9 = -27 then you divide -9 to -27 which is 3 so b = 3.
To find a:
2a - 3b = -11
a + 3b = 8
I multiplied a + 3b = 8 by -1 and 2a - 3b = -11 by -1 as well.
Your equation will look like this when you solve for a:
-2a + 3b = 11
-1a - 3b = -8
------------------
-3a = 3 then divide -3 to 3 which is -1 so a = -1.
Check to see if you have the correct answer by plugging in the number you got for a and b into the equation and solve.
1. 2(-1) -3(3) = -11
-2 - 9 = -11
2. -1 + 3(3) = 8
-1 + 9 = 8
Answer:
x = 1 ±√89
Step-by-step explanation:
We have the equation:
(x+7)(x-9) = 25
Using distributive property:
x(x-9) + 7(x-9) = 25
x²- 9x + 7x - 63 -25 = 0
x²- 2x - 88 = 0
To complete squares we need to add and subtract 1, as follows:
x²- 2x - 88 +1 -1 = 0
x²- 2x +1 -88 -1 = 0 (this is a perfect square)
(x - 1)² - 89 = 0
Solving for x:
(x - 1)² = 89
x - 1 = ±√89
x = 1 ±√89
28 white ducks swimming in pond
2*(28 white ducks) = 56 brown ducks flew and landed in pond
(28 white ducks)/2 = 14 white ducks remained in the pond
Ducks remaining in the pond (at this point):
(14 white ducks) + (56 brown ducks) = <u><em>70 ducks in all</em></u>
