<span> 5×-(3+9)
Substitute 6 for x
5(6)-(3+9)
Add 9 to 3
5(6)-12
Multiply 5 by 6
30-12
Final Answer: 18</span>
Answer:
a and b.
Step-by-step explanation:
I’ll explain by giving an example.
Let’s say that: a=3;b=4;c=5; => they all are consecutive -> their sum is 12.
=> if we use a) n=3 => 3*n+3=3*3+3=12 => correct.
b) n+(n+1)+(n+2)= 3+4+5=12=> correct.
c)n+2n+3n=3+6+9=18=>incorrect.
d)3n=3*3=9=>incorrect.
There is 2 ways to solve this type of question.
Method 1
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Formula
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a² + b² = c²
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Apply the formula
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(7√2)² + (7√2)² = c²
c² = 98 + 98
c² = 196
c = √196
c = 14
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Ans: The diagonal length is 14cm
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Method 2
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Identify the triangle
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This is a special triangle
45° - 45° - 90°
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Property of the Angles
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x - x - x√2
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Find hypotenuse
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Given that the non-hypotenuse is 7√2
Hypotenuse = (7√2)(√2)
Hypotenuse = 7 x 2
Hypotenuse = = 14cm
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Ans: The diagonal length is 14cm
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