44
simply because it asks what the heaviest is
D = k + 20
j = 3k - 120
d = j
k + 20 = 3k - 120
20 + 120 = 3k - k
140 = 2k
140/2 = k
70 = k.....so Katie weighs 70 lbs
David and Johnathan each weigh 90 lbs
Answer:
121.50
Step-by-step explanation:
Let x be the earnings
2x+10 = 253
Subtract 10 from each side
2x+10-10 = 253-10
2x = 243
Divide by 2
2x/2 = 243/2
x = 121.50
Answer:
a.
Step-by-step explanation:
Basically you're solving for both variables here.
I prefer elimination method so that is what I used.
I started off by multiplying each equation in order to get one of the variables at the same value so it would be possible to cancel it out.
Multiplying the first equation by 3 gave me,
12x + 15y = 69
Then I multiplied the second equation by 4,
-12x + 28y = -56
As you can see, it's not possible to cancel out the x variable.
12x + 15y = 69
+(-12x + 28y = -56)
_____________
13y = 13
Then just solve for y which gives you -1.
After you have one variable solved simply insert it into one of the original equations to find the other variable.
4x + 5(-1) = 23
4x - 5 = 23
4x = 28
x = 7.
And there you have it! Hope this helped!