Answer:
P = -12xy - 56y - 42x + 8
Step-by-step explanation:
P = 2L + 2W
P = 2(4 - 7(3x + 4y)) + 2(3x(-2y))
P = 8 - 14(3x + 4y) + 6x(-2y)
P = 8 - 42x - 56y - 12xy
P = -12xy - 56y - 42x + 8
Answer:
Step-by-step explanation:
f(x) = x^2 + 4x + 4
f(x + a) = (x + a)^2 + 4(x + a) + 4
f(x + a) = x^2 + 2ax + a^2 + 4x + 4a + 4 Now combine like terms and use the distributive property.
f(x + a) = x^2 + (2a + 4)x + a^2 + 4a + 4
We are told that f(x + a) = x^2 - 6x + 9
So that means that
2a + 4 = - 6 Subtract 4 from both sides.
2a = - 6 - 4
2a = - 10 Divide by 2
a = - 10/2
a = - 5.
But you are not finished. You have to check the last part.
a^2 + 4x + 4 = 9
(a + 2)^2 = 9
Take the square root of both sides
sqrt(a+ 2)^2 = +/- 3
a+2 = 3
a = 1.
Does this work or is it extraneous? It is extraneous because it will not work for 2(a) + 4 = - 6
You get 6 = - 6 which is not correct. But you did give the second best answer.
a + 2 = - 3
a = - 3 - 2
a = - 5 which agrees with your previous answer.
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This is an extremely hard or tricky or sneaky problem. It takes a lot of conniving to get the right answer and 1 is not a left field answer. It just does not happen to be correct.
Answer:
x = √21.
Step-by-step explanation:
Triangles ADB and BCD are similar.
So their corresponding sides are in the same ratio:
x / 7 = 3 / x
x^2 = 21
x = √21.
