Answer:
Index fossil, any animal or plant preserved in the rock record of the Earth that is characteristic of a particular span of geologic time or environment. A useful index fossil must be distinctive or easily recognizable, abundant, and have a wide geographic distribution and a short range through time.
Step-by-step explanation:
Answer: x = 3
Step-by-step explanation:
-5 -x = -8
-× = -8 + 5
-x = -3
x = 3
Answer:
1655
Step-by-step explanation:
Note the common difference d between consecutive terms of the sequence
d = - 1 - (- 4) = 2 - (- 1) = 5 - 2 = 8 - 5 = 3
This indicates the sequence is arithmetic with sum to n terms
= 
[ 2a₁ + (n - 1)d ]
Here a₁ = - 4, d = 3 and n = 90, thus
= 
[ (2 × - 4) + (89 × 3) ] = 45(- 8 + 267) = 45 × 259 = 1655
Answer:
18+12.125π units²
Step-by-step explanation:
The diameter of the semicircle can be found by the use Pythagoras theorem.
Δx²+Δy²=d²
Δx=3--1=4
Δy=3--6=9
d²=4²+9²
d=√(16+81)
Area=πr²/2
=π×(√(16+81)/2)²÷2
=[π×(97)/4]/2
=97π/8
=18+12.125π units²
97π/8 is equivalent to 18+12.125π units²
Answer: " 4x + 2xy - 7pq " .
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Explanation:
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Given: " <span>4x - 7xy + 9xy - 7pq " ; Simplify the expression;
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Combine the "like terms:
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-7xy + 9xy = 2xy ;
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Now, rerewrite the expression, substituting the "-7xy + 9xy"; with " + 2xy" ;
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</span>→ " 4x + 2xy - 7pq " .
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