SOLUTION:
Let whole number = x
x + 2x^2 = 21
2x^2 + x - 21 = 0
2x^2 + 7x - 6x - 21 = 0
x ( 2x + 7 ) - 3 ( 2x + 7 ) = 0
( 2x + 7 ) ( x - 3 ) = 0
2x + 7 = 0
2x = - 7
x = - 7 / 2
OR
x - 3 = 0
x = 3
ANSWER:
Therefore, as 3 is a whole number while - 7 / 2 isn't a whole number, the whole number must be 3.
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Answer:
The square root of 144 will be 12
Answer:
12.5
Step-by-step explanation:
12.5 multiplied by 20 is 250 which you divide by 2 to get the area. it plugs in to the triangle area formula which is 1/2 base times height.
Answer:
1) 378.1 in²
2) 8.4 m²
Step-by-step explanation:
Area of sector= 
1) Area of sector

2) Area of sector

Here is the equation:

Since both decimals are negative, the answer will be positive.
- Negative times Negative = Positive
Divide both sides by -3.9 to leave the variable alone:

r is equal to 4 → r = 4