Answer:
The length is 7 m
The width is 10 m
Step-by-step explanation:
length = x
width = 2x - 4
length * width = area
It is given that the area is 70 
From there
x * (2x - 4) = 70
- 4x = 70
- 4x - 70 = 0
- 2x - 35 = 0
Now we have a quadratic equation, which is a + bx + c = 0, where a 
0
In this equation a = 1, b = -2 and c = -35
Discriminant (D) formula is b² - 4ac
D = 
- 4 * 1 * (-35) = 144 > 0
This discriminant is more than 0, so there are two possible x
Their formulas are 
and 
= 
= -5 < 0 (the length of the rectangle has to be more than 0, so we don't use this x)
= 
= 7 > 0 (this one is right)
Calculating the dimensions
length = x = 7 (m)
width = 2x - 4 = 2 * 7 - 4 = 10 (m)
Answer:
solution is 9a^16
Step-by-step explanation:
(6)^2= 36
(a^5)^2= a^25
36a^25/(9a^9)
(36/9)= 4
(a^25)/(a^9)= a^(25-9)= a^16
Answer:
Simplifying
x = -25
Step-by-step explanation:
Reorder the terms:
10x + -6(5 + 2x) = 20
10x + (5 * -6 + 2x * -6) = 20
10x + (-30 + -12x) = 20
Reorder the terms:
-30 + 10x + -12x = 20
Combine like terms: 10x + -12x = -2x
-30 + -2x = 20
Solving
-30 + -2x = 20
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '30' to each side of the equation.
-30 + 30 + -2x = 20 + 30
Combine like terms: -30 + 30 = 0
0 + -2x = 20 + 30
-2x = 20 + 30
Combine like terms: 20 + 30 = 50
-2x = 50
Divide each side by '-2'.
x = -25
Answer:
B) (4x-5i)(4x+5i)
Step-by-step explanation:
The expression can be treated as the difference of squares, and factored accordingly. That factoring is ...
a² -b² = (a -b)(a +b)
__
Here, we have ...
a² -b² = 16x² -(-25)
a² = 16x² ⇒ a = 4x
b² = -25 ⇒ b = √-25 = 5i
Then the factoring is ...
(a -b)(a +b) = (4x -5i)(4x +5i)
