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:
471.2 cm³ missing
Step-by-step explanation:
jars are cylinders
volume of cylinder = π * r² * h
h=10
r=5
v=785.4 cm³ of a full jar
r stays the same = 5
h = 4
v= 314.2 cm³ left in the jar
whats missing is the full-left
785.4-314.2=471.2 cm³ missing
Only one because there is one variable and the combined coefficients of x are non-zero.
(0.75(x+40)=0.70(x+20), 0.05x=14-30=-16, x=-320)
Answer:
4
Step-by-step explanation:
