So x + y = 45, and 4x + 5y = 195. Get y by itself. Subtract x from both sides in the first equation to get y = 45 -x, and subtract 4x from the second equation to get 5y = 195 - 4x. Divide by 5 to both sides to get y = 39 - 4/5x. 39 - 4/5x = 45 - x. Add x to both sides to get 39 - 1/5x = 45. Subtract 39 from both sides to get -1/5x = 6. Divide by -1/5 to get x = -30, or 30. In the first equation, do 30 + y = 45. Subtract 30 from both sides to get y = 15. Check. 4(30) + 15(5) = 195, or 120 + 75 = 195.
Answer:
1. 25
2. 5.7
3. 10.7
4. 204
5. 100.5
Step-by-step explanation:
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<h3>✽ - - - - - - - - - - - - - - - ~Hello There!~ - - - - - - - - - - - - - - - ✽</h3>
➷ Expand them all to see if you get the expression:
2(3x - 4) ==> 6x - 8
2(3x + 4) ==> 6x + 8
2(4x + 6) ==> 8x + 12
2(3x + 8) ==> 6x + 16
As you can see, the correct option is B. 2(3x + 4)
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Answer:
The first statement is true.
Step-by-step explanation:
The function is f(x) = - (x + 6)(x + 2)
⇒ f(x) = - x² - 8x - 12
Now, condition for a function f(x) to be increasing at x = a is f'(a) > 0.
Now, f(x) = - x² - 8x - 12
⇒ f'(x) = -2x - 8 {Differentiating with respect to x}
Now, f'(a) = -2a - 8 {Here a can be any real value}
And, the condition for increasing function at x = a is
- 2a - 8 > 0
⇒ - 2a > 8
⇒ a < - 4
Therefore, the first statement is true i.e. the function is increasing for all real values of x where x < – 4. (Answer)
