Answer:
The answer is -77
Step-by-step explanation:
Ok, so assuming by x2 you mean x squared, I will solve this. So basically when you have a function, f(-7) would mean that you would have to replace all the x's in the equation with -7. So let's write that out. that would be f(-7) = -7^2 + (-7*4). So now according to PEMDAS, you would solve the exponent first, and -7^2 is equal to -49, because when you solve it you would do -(7^2), which is -(49), which is then -49. So now you have f(-7)= -49+ (4*-7). Solving for (4*-7), you get -28. This leaves you with -49 + (-28), which is -49 - 28. Simplifying that, you get the answer, which is -77.
Answer:
270 s
Step-by-step explanation:
4 minutes = 240s
add the other 30s
boom
We don't know which side your triangle is sitting on, so the 'height'
could be any one of three values.
Here are the two simple tools that tell you everything you want to
know about a 30°-60°-90° triangle. These are worth memorizing:
-- The side opposite the 30° angle is 1/2 of the hypotenuse.
-- The side opposite the 60° angle is 1/2 of the hypotenuse times √3 .
I memorized them exactly 60 years ago. They've been very useful,
and as far as I know, they haven't changed.
Answer: it cost a customer $7.25 to buy five tulips and $10.5 to buy six roses.
Step-by-step explanation:
Let x represent the cost of 1 tulip.
Let y represent the cost of 1 rose.
The price of each tulip is the same and the price of each roses the same. One customer bought seven tulips and nine roses for $25.90. This means that
7x + 9y = 25.9 - - - - - - - - - - - - - - 1
Another customer bought for four tulips and eight roses for $19.80. This means that
4x + 8y = 19.8- - - - - - - - - - - - - - - 2
Multiplying equation 1 by 4 and equation 2 by 7, it becomes
28x + 36y = 103.6
28x + 56y = 138.6
Subtracting, it becomes
- 20y = - 35
y = - 35/ - 20
y = 1.75
Substituting y = 1.75 into equation 2, it becomes
4x + 8 × 1.75 = 19.8
4x + 14 = 19.8
4x = 19.8 - 14 = 5.8
x = 5.8/4
x = 1.45
The cost of 5 tulips would be
1.45 × 5 = $7.25
The cost of 6 roses would be
1.75 × 6 = $10.5
