Answer:

Step-by-step explanation:
→ First understand what Pythagoras theorem is
Pythagoras is a theorem used to find the hypotenuse (the side opposite to the right-angle) of a triangle. We would need the base lengths as well the height in order to use Pythagoras.
→ State the formula and identify the letters
a² + b² = c² ⇒ where 'a' is 380cm, 'b' is 290cm and 'c' is what we are trying to work out
→ Substitute in the values into the formula
380² + 290² = c²
⇒ Simplify
144400 + 84100 = c²
⇒ Collect the numbers together
228500 = c²
⇒ Square root both sides to find 'c'
478.0167361 = c
→ The length of the diagonal is 478.02
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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Equation a and equation c
Answers:
- b = -19
- b = -11
- b = -9
- b = 19
- b = 11
- b = 9
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Explanation:
Here are all the ways to multiply to 18 when using integers only:
- -1*(-18) = 18
- -2*(-9) = 18
- -3*(-6) = 18
- 1*18 = 18
- 2*9 = 18
- 3*6 = 18
Sum each pair of factors to find out a possible value of b.
- -1 + (-18) = -19
- -2 + (-9) = -11
- -3 + (-6) = -9
- 1 + 18 = 19
- 2 + 9 = 11
- 3 + 6 = 9
Therefore, the possible values of b are
- b = -19
- b = -11
- b = -9
- b = 19
- b = 11
- b = 9
which are the final answers.
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An example:
Let's say b = 11. This would mean
becomes 
It would factor to
since it was stated earlier that:
2+9 = 11
2 * 9 = 18
You can use the FOIL rule, distributive property, or the box method to confirm that
is a true equation for all real numbers x.
This same idea applies for the other values of b.
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If you're curious why this works, consider multiplying the two factors (x+p) and (x+q)
Use the FOIL rule to get 
The middle term
has the components add to the coefficient, while those same two components multiply to get the last term. This is why when factoring we're looking for two numbers that multiply to 18, and also add to the value of b (which in the case of the last example was 11).