Answer:
3x²- 1
Step-by-step explanation:
f(-3) when f(x) = -x²+1
(-x²+1) × -3
3x²- 1
Answer:
= -5
Step-by-step explanation:
You are buying 2 items so let's use two different variables to represent each:
p = number of tubes of paint
b = number of disposable brushes
cost = price per item × number of items
Equations from information given:
4p + 0.50b = 20 ← from the first 2 sentences
2p = b ← if there are twice as many brushes as paint tubes you need 2 times paint tubes to equal number of brushes
Solve the problem by using substitution... 1b equals 2p so replace b with that:
4p + 0.50(2p) = 20
4p + 1p = 20 ← 0.50 is half so half of 2p is 1p
5p = 20 ← combine like terms
p = 4 ← divide both sides of the equation by 5
Recall the equation 2p = b replace p with 4
2(4) = b
8 = b
ANSWER:
You purchased 4 tubes of paint and 8 disposable brushes.
Here is how I completed the problem:
I started by creating a ratio:

<em>Where 'x' is the desired amount of the 18% solution of sulfuric acid.
</em>From here, I solved for 'x':
<em>
</em>







∴You will need to add 1080ml of 18% Sulfuric Acid in order to obtain a 15% solution.
<span>4x - 15 = 3 </span>
<span>4x = 3 + 15 </span>
<span>4x = 18 (divide both sides by 4 to get x) </span>
<span>4x/4 = 18/4 </span>
<span>x = 4.5 </span>