We can use linear combinations of the equations to eliminate variables.
3x - 4y = 1
-2x + 3y = 1
To eliminate y we'll make the linear combination of 3 times the first equation minus four times the second.
9x - 12y = 3
-8x + 12y = 4
Adding,
x = 7
We could solve for y directly but let's use another linear combination, twice the first plus three times the second:
2(3x - 4y) + 3(-2x + 3y)= 2(1)+3(1)
y = 5
Check: 3(7)-4(5)=1 good. -2(7)+3(5)=1 good.
Q18 Answer: (7,5)
y = -3x + 5
5x - 4y = -3
4y +1(5x - 4y) = 4(-3x + 5) + 1(-3)
5x = -12x + 20 -3
17 x = 17
x = 1
y = -3(1) + 5 = 2
Check: 5(1) - 4(2) = -3 good
Q19 Answer (1,2)
6x + 5y = 25
x = 2y + 24
6x = 12y + 144
5y = 25 - 12y - 144
17y = -119
y = -119/17= -7
x = 2y+24= 10
Check: 6(10)+5(-7)=25 good 2y+24=2(-7)+24=10=x good
Q20 Answer (10,-7)
3x + y = 18
-7x + 3y = -10
9x + 3y = 54
9x - -7x = 54 - -10
16x = 64
x=4
y = 18 -3x = 18-12=6
Check: 3(4)+6=18 good, -7(4)+3(6)=-10 good
Q21 Answer: (4,6)
Answer:
13.73 in^2 because the circle's area is 50.27 in^2
L X W = A. So, if the top of the table is 4 ft, you need to find the sq. route of 4. (HINT: the sq. route can be doubled to equal the area.
1. 15+37=?
- 15=10+5 (given on the diagram)
- 37=30+7 (given on the diagram)
- add digits to digits 5+7=12=10+2
- add tens to tens 10+30+10=50
- add tens and digits 50+2=52.
2. 22+49=?
- 22=20+2 (given on the diagram)
- 49=40+9 (given on the diagram)
- add digits to digits 2+9=11=10+1
- add tens to tens 20+40+10=70
- add tens and digits 70+1=71.
3. 38+26=?
- 38=30+8 (given on the diagram)
- 26=20+6 (given on the diagram)
- add digits to digits 8+6=14=10+4
- add tens to tens 30+20+10=60
- add tens and digits 60+4=64.
Answer: 1) 52; 2) 71; 3) 64.
Answer:
C 
Step-by-step explanation:
