2x+y=-4
5x+3y=-6
multiply first equaton by -5 and second by 2 then add them
-10x-5y=20
<u>10x+6y=-12 +</u>
0x+1y=8
y=8
the y value is 8
Answer:
within ±1.96 standard deviations of the sample mean
Step-by-step explanation:
A 95% confidence interval is found using the formula C = 1 - α, and some other stuff, but let's focus on that for now. Using the formula:
.95 = 1 - α
α = .05
If α = .05, that means a 2-sided confidence interval would be found using the sample mean and the Z-score Z(subscript α/2), or Z.₀₂₅ because α AKA .05 divided by 2 = .025. From there, you take this either to your calculator or a Z-table (or perhaps you have a chart that lists the common CI values), and see that for the area to be .025 beneath a standard normal curve, your Z value is ±1.96 ("plus or minus" because we're considering a 2-sided confidence interval).
Answer:
80
Step-by-step explanation:
Substitute the given values into the expression
b²(a - 2c)
= (- 4)²(3 - 2(- 1))
= 16(3 + 2)
= 16 × 5
= 80
