Answer:
point-slope form: y - 1 = -4/5(x - 8)
slope-intercept form: y = -4/5x + 7.4
Step-by-step explanation:
Find slope using the points (8, 1) and (-2, 9):
m = (y₂ - y₁) / (x₂ - x₁)
= (9 - 1) / (-2 - 8)
= 8 / -10
m = -4/5
Find y-intercept using slope m from above and anyone of the given points, let's use (8, 1):
y = mx + b
1 = -4/5(8) + b
1 = -6.4 + b
b = 7.4
Use slope m and y-intercept b above to form equation of line in slope-intercept form:
y = mx + b
y = -4/5x + 7.4
For point slope form use slope m from above and a point, again let's use (8, 1):
y - y₁ = m(x - x₁)
y - 1 = -4/5(x - 8)
Answer:
- Burgers - $8.29 and fries - $4.39
Step-by-step explanation:
<u>Let burgers - b, fries - f</u>
- 8b + 3f = 79.49
- 12b + 6f = 125.82
<u>Double the first equation and subtract the second equation:</u>
- 16b + 6f - 12b - 6f = 2(79.49) - 125.82
- 4b = 33.16
- b = 33.16/4
- b = 8.29
<u>Find f:</u>
- 8(8.29) + 3f = 79.49
- 3f = 79.49 - 66.32
- 3f = 13.17
- f = 13.17/3
- f = 4.39
<span>1. Solve the system by substitution -2x+y=-11, 3x-4y=11.
</span>-2x+y=-11<span>
y = 2x-11
</span><span>3x-4y=11
</span>3x-4(2x-11)=11
3x -8x + 44 = 11
-5x = -33
<span>x =33/5
y = 11/5
</span><span>2. Solve the system using elimination- 2x+6y=-12, 5x-5y=10.
</span><span>(-2x+6y=-12)5
</span>-10x + 30y = -60
<span>(5x-5y=10)2
</span>10x - 10y = 20
Adding the two equations,
<span>-10x + 30y = -60
</span><span>10x - 10y = 20
</span>
20y = -40
y = -2
x = 0
<span>3. What is the solution of the following system?-3x-2y=-12, 9x+6y=-9.
</span><span>-3x-2y=-12
</span>y = -3/2 x + 6
<span>9x+6y=-9
</span>y = -3/2 x - 3/2
Since the slopes are equal then they are parallel lines so they never meet at one point.
What you want to do is take one of the 2 equations and isolate one variable. you will then use the value that you find for the variable and plug it back into the other equation. here is how:
This would be easiest to do with the second equation in the set since the x is not being multiplied by anything. So lets isolate the x in the second equation.
add 0.9y to both sides and you get:
x=4.5+0.9y
we now know what x is equal to in terms of y. so lets replace the x in the first equation with the new value. You get:
1.5(4.5+0.9y)-1.9y=-29
Now just solve for y:
6.75+1.35y-1.9y=-29
1.35y-1.9y=-35.75
-0.55y=-35.75
y=65
so now you know that y=65 so plug 65 in as y in the second equation to find x
x-0.9*65=4.5
Now simply solve for x
x-(-58.5)=4.5
x+58.5=4.5
x=-54
Hope this helped! :)
