First picture)
I: 5x+2y=-4
II: -3x+2y=12
add I+(-1*II):
5x+2y-(-3x+2y)=-4-12
8x=-16
x=-2
insert x=-2 into I:
5*(-2)+2y=-4
-10+2y=-4
2y=6
y=3
(-2,3)
question 6)
I: totalcost=115=3*childs+5*adults
II: 33=adults+childs
33-adults=childs
insert childs into I:
115=3*(33-adults)+5*adults
115=99-3*adults+5*adults
16=2*adults
8=adults
insert adults into II:
33-8=childs
25=childs
so it's the last option
question 7)
a) y<6 and y>2 can also be written as 2<y<6, so solution 3 exist for example
b) y>6 and y>2 can also be written as 2<6<y, so solution 7 exist for example
c) y<6 and y<2 inverse of b: y<2<6, so for example 1
d) y>6 and y<2: y<2<6<y, this is impossible as y can be only either bigger or smaller than 2 or 6
so it's the last option
question 8)
I: x+y=12
II: x-y=6
subtract: I-II:
x+y-(x-y)=12-6
2y=6
y=3
insert y into I:
x+3=12
x=9
(9,3)
question 9)
I: x+y=6
II: x=y+5
if you take the x=y+5 definition of II and substitute it into I:
(y+5)+y=6
which is the second option :)
Answer: It makes 30 circles in a minute
Step-by-step explanation:
Cirle every 2 seconds
A minute is 60 seconds
So you divide those to get your answer
60 divided by 2= 30
Answer:
Es cierto se usan 16 paquetes de salchichas y 12 paquetes de panes para pancho.
Step-by-step explanation:
Lo que debemos hacer en este caso es dividir la cantidad total de panchos primero por la cantidad de unidades de salchichas que vienen en su paquete y segundo por la cantidad de unidades de panes para panchos que vienen en su paquete, si el resultado nos da un numero entero podemos decir que usa una cantidad completa de paquetes de salchichas y de panes:
96/6 = 16
96/8 = 12
Es decir que para 96 panchos se usan 16 paquetes de salchichas y 12 paquetes de panes para pancho, por lo tanto es cierto.
Answer: 
Step-by-step explanation:
Since, The LCM of numbers given numbers
,
,
and
is
.
Thus, the number that gives 1 as reminder and is the multiple of 7 is 
Where n is any positive integer,
Since, For
,
The number is, 
Which is divisible by
.
Thus, the required number is 301.
Note : For n = 1, 2 3 and 4, numbers are 61, 121, 181 and 241
But they are not the multiple of 7.