Simplify the expression -2 (x + 4 + 5y).
1 answer:
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Step-by-step explanation:
Well in general, we can represent subtraction as:
"z" represents the difference, and it really just represents x with y taken away. So if we were to "give back" this y value, we should get "x".
This means that:
So one way to check, is adding the value that's being subtracted (y value) and the difference (z value), this should get you the value that is being subtracted from (x value). If you don't get the original value that's being subtracted from (x-value) then you know the answer you got is wrong.
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6.
Since the area is that of a square, you know that all side lengths are the same.
Area is base times height (A = bh), but since base and height are the same for a square, you get the formula A = a².
The length of the side of a square with an area of 144 in² is 12 in.
7.
Rational number.
8.
This is a right triangle; use the Pythagorean Theorem to find missing lengths of right triangles. Pythagorean Theorem: a² + b² = c², where c is the hypotenuse of the triangle.
Plug in your leg lengths:
a² + b² = c²
8² + x² = 21²
64 + x² = 441
x² = 377
x = 19.4
6.
Since the area is that of a square, you know that all side lengths are the same.
Area is base times height (A = bh), but since base and height are the same for a square, you get the formula A = a².
The length of the side of a square with an area of 144 in² is 12 in.
7.
Rational number.
8.
This is a right triangle; use the Pythagorean Theorem to find missing lengths of right triangles. Pythagorean Theorem: a² + b² = c², where c is the hypotenuse of the triangle.
Plug in your leg lengths:
a² + b² = c²
8² + x² = 21²
64 + x² = 441
x² = 377
x = 19.4