Answer:
y = 5, -4
Step-by-step explanation:
To solve proportions you cross-multiply.
Now that we have 8 = y^2 - y - 12, we must make the entire trinomial equal to 0 by subtracting 8 from both sides.
y^2 - y - 20 = 0
Factor the trinomial.
(y - 5)(y + 4) = 0
Make both factors equal to 0 to solve for both values of y.
- y - 5 = 0 --> y = 5
- y + 4 = 0 --> y = -4
y = 5, -4
Answer:
a = 3 7/18 or 3.388889
Step-by-step explanation:
First, you want to get the a by itself, so you would subtract 4 from the left side of the equals sign.
6a + 4 = 61 / 3 + 4
-4 -4
6a = 61 / 3
By doing that, they cancel each other out, so you are left with
6a = 61 / 3
Then you want to get a by itself, so you divide 6 from both sides.
6a / 6 = 61 / 3 / 6
Remember that 6 can also be written as 6/1
Remember that dividing a fraction is multiplying the reciprocal.
6a / 6 = 61 / 3 / 6 / 1
When dividing fractions remember to Skip the first fraction, Flip the second fraction, and Multiply the two fractions together.
61 / 3 x 1 / 6
skip multiply flip
Multiply across the top, and across the bottom.
61(1) and 3(6)
Then you get
61 / 18
So a = 61 / 18
If you want to convert that to a mixed number, it would be 3 7 / 18
If you want that in a decimal, it would be 3.388889
Your formula here is A=pir^2
Plug in the numbers but instead use 22/7 for pi
A=(22/7)(21)^2
A=22/7*441=1386
Answer is 1386 sq inches
Answer:
$43.20
Step-by-step explanation:
The price with tax is 100% + 8% = 1.08 times the price before tax. The discount multplies that price by 100% -20% = 0.80. The discount multiplier is the same whether the discount is applied before or after the tax.
The combined effect of the two multipliers is ...
... 1.08 × 0.80 = 0.864
so the discounted price with tax added is 0.864 × $50 = $43.20
_____
Perhaps you're supposed to figure the tax (8% of $50 = $4), add the tax ($50 +4 = $54), then subtract the discount (20% of $54 = $10.80) to get
$54.00 -10.80 = $43.20
