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3 years ago

How many solutions are there to the equation n^2-13n=-40

Mathematics

2 answers:

Marizza181 [45]3 years ago

8 0

It has 2 real solutions which are 5 and 8

Nitella [24]3 years ago

4 0

Answer:

n = 5

n = 8

Step-by-step explanation:

n^2 - 13n = -40

Equate everything to zero

n^2 - 13n + 40 = 0

Factorise

(n - 5)(n - 8) = 0

Either

n - 5 = 0

Add 5 to both sides

n - 5 + 5 = 0 + 5

n = 5

n - 8 = 0

Add 8 to both sides

n - 8 + 8 = 0 + 8

n = 8

n = 5 or

n = 8

It has two real solutions

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A sales person earns a commission based on the number and type of vehicle sold. A person selling 6 cars and 3 trucks earns 4,800

AURORKA [14]

Assign variables to you unknowns.

c = $ cars
t = $ trucks

6c + 3t = 4800
8c + t = 4600

use substitution or elimination to solve the system of equations.

using elimination.. multiply second equation by -3 and add to the other to combine equations into one.

6c + 3t = 4800
-3(8c + t = 4600)
---------------------------
-18c + 0 = -9000
c = 9000/18
c = 500 $

use this in one of the equations to find the cost of a truck.

8(500) + t = 4600
4000 + t = 4600
t = 4600 - 4000
t = 600 $

question asks
2(500) + 3(600) =
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3 0

2 years ago

What 2 numbers add to get 2 and multiply to 4

rusak2 [61]

Factor 4
4=1 times 4
2 times 2
they don't add to 2
set up equation
x+y=2
xy=4

first equation, subtract x from both sides
y=2-x
subsitute for y
x(2-x)=4
distribute
2x-x^2=4
add x^2
2x=x^2+4
subtract 2x
0=x^2-2x+4
use quadratic formula which is
if you have ax^2+bx+c=0 then
x= $\frac{ -b+/-\sqrt{b^{2}-4ac} }{2a}$ so

1x^2-2x+4=0
a=1
b=-2
c=4
x= $\frac{ -(-2)+/-\sqrt{(-2)^{2}-4(1)(4)} }{2(1)}$
x= $\frac{ 2+/-\sqrt{4-16} }{2}$
x= $\frac{ 2+/-\sqrt{-12} }{2}$
we have $\sqrt{-12}$ and that doesn't give a real solution
therefor there are no real solutions
but if you want to solve fully
x= $\frac{ 2+/-2\sqrt{-3} }{2}$
i= $\sqrt{-1}$
x= $\frac{ 2+/-2i\sqrt{3} }{2}$
x= $1+/-i\sqrt{3}$
x= $1-i\sqrt{3}$ or x= $1+i\sqrt{3}$ (those are the 2 numbers)

6 0

3 years ago

Someone plz help me. There are 2 answer choices

givi [52]

ik the first answer choice is false

3 0

2 years ago

Read 2 more answers

8th grade khan academy

satela [25.4K]

Answer:

d = 11t - 20