Answer:
12
Step-by-step explanation:
x will be the age of her younger brother
34 = 2x + 10
She is ten more than twice his age
34 = 2x + 10
- 10 - 10
Then she twice his age
24 = 2x
÷2 ÷2
So his age is 12
x = 12
Answer:
D. 10 square root 3 is your answer
Step-by-step explanation:
Here is what you do.
<em>square root 30 = 3 x 2 x 5 </em>
<em>square root 10 = 2 x 5</em>
Add them together.
<em>3 x 2 x 2 x 5 x 5 </em>
<em>3 x 4 x 25.</em>
4 and 25 can come out of the square root.
<em>2 x 5 = 10</em>
10 square root 3 is your answer.
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 :)
To write the equation of a line I need slope and y intercept (0,y)
I have y intercept (0,7) of +7 as written in the equation
The equation y=-5/4x + 11/4 has a slope of -5/4
To get perpendicular slope is negated reciprocal
so take -5/4 and flip it -4/5 and change the sign (in this case negative to positive) 4/5
so the new equation is y=4/5x +7 (third one)
