Answer:
(-3,1)
Step-by-step explanation:
9x+8y=-19
7x+9y=-12
I'll assume the question is to find the solution to these equations. The solution will be the point (x,y) where the two lines intersect. The intersection is the one point that satisfies both equations (the smae value of (x,y) works in both.
We can either solve matematically of graph to find the intersection. I'll do both, and hope the answers are identical.
<u>Matematically</u>
Rearrange either equation to isolate one of the variables (either x or y). I'll take the second and isolate x:
7x+9y=-12
7x = -9y - 12
x = (-9y - 12)/7
Now use this definition of x in the other equation:
9x+8y=-19
9((-9y - 12)/7) + 8y = -19
(-81y - 108)/7 + 8y = -19
-81y - 108 + 56y = - 133
-25y = -25
<u>y = 1</u>
If y = 1, then:
9x+8y=-19
9x+8(1)=-19
9x = -27
<u>x = -3</u>
<u></u>
<u>The solution is (-3,1)</u>
<u>Graphing</u>
<u></u>
Graph both lines and look for the intersection. The attached graph shows the lines cross at (-3,1).
The solution, bu both approachjes, is (-3,1)
Answer:$128
Step-by-step explanation:
If $1=6.25 rands then we must divide 800 by 6.25
Answer:
358
Step-by-step explanation:
Answer:
90% confidence interval for the mean is between a lower limit of 3.08 days and an upper limit of 3.18 days.
Step-by-step explanation:
Confidence interval is given as mean +/- margin of error (E)
mean = 3.13 days
sd = 0.48 day
n = 250
degree of freedom = n-1 = 250-1 = 249
confidence level (C) = 90% = 0.9
significance level = 1 - C = 1 - 0.9 = 0.1 = 10%
critical value (t) corresponding to 249 degrees of freedom and 10% significance level is 1.65153
E = t×sd/√n = 1.65153×0.48/√250 = 0.05 day
Lower limit of mean = mean - E = 3.13 - 0.05 = 3.08 days
Upper limit of mean = mean + E = 3.13 + 0.05 = 3.18 days
90% confidence interval is (3.08, 3.18)
Answer:
The equation of the line would be y = -2x + 8
Step-by-step explanation:
In order to find this, we first need to find the slope of the original equation. We can do this by solving for y.
x - 2y = -6
-2y = -x - 6
y = 1/2x + 3
Now that we have a slope of 1/2, we know the new perpendicular line will have a slope of -2. We know this because perpendicular lines have opposite and reciprocal slopes. This means we flip it and change the sign. Now we can use this slope along with the point to find the equation.
y - y1 = m(x - x1)
y - 2 = -2(x - 3)
y - 2 = -2x + 6
y = -2x + 8
