Start with the solution
x=-25
use the reverse of what they asked
they wanted division and addition
we use multiplication and subtract
ok
x=-25
we can use subtraction and multiplication in any order
minus 10 from both sides
x-10=-35
multiply both sides by 4
4(x-10)=-140
4x-40=-140 is a possible equation
Answer:
50 years
Step-by-step explanation:
use the simple interest formula :
PRT/100
P is the principle (5000)
R is the rate of interest (4)
T is the time taken (x- unknown)
the amount at the end is double the amount invested = 5000*2 = 10000
(5000*4 * x )/100 = 10000
20000x/100=10000
20000x = 100*10000
20000x = 1 000 000
x= 1 000 000/ 20 000
x = 50
it will take<u> 50 years </u>
All primes are odd, except two. Therefore the sum of the first million primes is one even number plus 999999 odd numbers. Since odd*odd = odd, the first million primes must be even + odd = odd.
An odd number obviously has an odd final digit, so the only option that can be firmly rules out is b (which is even).
-3x + y - 2z = 10 |* -1
3x - y +2z = -10
5x -2y -2z = 12
--------------------------- I add these equations term by term
8x - 3y = 2
-3x + y - 2z =10 ⇒ -3x + y - 2z =10
x -y +z = 23 | *2 2x - 2y + 2z = 46
----------------------------- I add these eq.
-x -y = 56
8x - 3y = 2
-x -y = 56
this is the system after i reduce it ( it has only two variables x and y)
