Answer:
7
Step-by-step explanation:
So, substitute in your 4 for r, 2(3) + 1. Multiply 2 and 3 to get 6 and then add a to get 7. I hope this helps :)
Hello from MrBillDoesMath!
Answer:
n = 5
Discussion:
Let the original number be "n" Translating the problem statement to mathematical symbolism:
n + 4 = 19 - 2n => add 2n to both sides
n + 2n + 4 = 19 - 2n + 2n => combine like terms
3n + 4 = 19 => subtract 4 from both sides
3n = 19 -4 = 15 => divide both sides by 3
n = 15/3 =5
Check: Does 5 +4 = 19 - 2(5)? Does 9 = 9? Yes. so the value for n is confirmed correct.
Thank you,
MrB
Use Pascal's Triangle
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
1 5 10 10 5 1
1 6 15 20 15 6 1
1 7 21 35 35 21 7 1
1 8 28 56 70 56 28 8 1
1 9 36 84 126 126 84 36 9 1 (this is the row you use)
So, the seventh term of (3x + 2y)^9 will be 84xy
Answer:
1 x=-2.5 y = -5.5
2. x=5 y=1
Step-by-step explanation:
1) What is the solution of the given system?
5x-y=-7
3x-y=-2
Multiply the second equation by -1
-1*(3x-y)=-1(-2)
-3x +y = 2
Now add the first equation to the modified second equation
5x-y=-7
-3x +y = 2
------------------
2x = -5
Divide each side by 2
2x/2 = -5/2
x = -2.5
Now we need to find y
-3x+y =2
-3(-2.5) +y =2
7.5 +y =2
Subtract 7.5 from each side
7.5 -7.5 +y =2-7.5
y = -5.5
2) what is the solution of the given system?
5x+7y=32
8x+6y=46
Divide the second equation by 2
8x/2+6y/2=46/2
4x+3y =23
Multiply the first equation by 4
4 (5x+7y)=32*4
20x+28y = 128
Now multiply the modified 2nd equation by -5
-5(4x+3y )=-5(23
)
-20x -15y = -115
Lets add the new equations together to eliminate x
20x+28y = 128
-20x -15y = -115
---------------------
13y = 13
Divide each side by 13
13y/13 =13/13
y=1
Now substitute back in to find x
5x+7y=32
5x +7(1) =32
5x +7 =32
Subtract 7 from each side
5x+7-7 =32-7
5x =25
Divide by 5
5x/5 =25/5
x=5
