Another one prince — let's solve it.
Here are the solutions for using the elimination method:
1. (a)
Given the equations:
2x+y=5(1)
x−y=1(2)
Step 1: Add equation (1) and equation (2) to eliminate y.
(2x+y)+(x−y)=5+1
3x=6
Step 2: Solve for x.
x=36
x=2
Step 3: Substitute x=2 into equation (2).
2−y=1
y=2−1
y=1
The solution is x=2,y=1.
1. (b)
Given the equations:
2x−y=5(1)
x+y=4(2)
Step 1: Add equation (1) and equation (2) to eliminate y.
(2x−y)+(x+y)=5+4
3x=9
Step 2: Solve for x.
x=39
x=3
Step 3: Substitute x=3 into equation (2).
3+y=4
y=4−3
y=1
The solution is x=3,y=1.
2. (a)
Given the equations:
x+2y=11(1)
2x−2y=10(2)
Step 1: Add equation (1) and equation (2) to eliminate y.
(x+2y)+(2x−2y)=11+10
3x=21
Step 2: Solve for x.
x=321
x=7
Step 3: Substitute x=7 into equation (1).
7+2y=11
2y=11−7
2y=4
Step 4: Solve for y.
y=24
y=2
The solution is x=7,y=2.
2. (b)
Given the equations:
2a−b=1(1)
3a+2b=19(2)
Step 1: Multiply equation (1) by 2 to make the coefficient of b equal to −2.
2(2a−b)=2(1)
4a−2b=2(3)
Step 2: Add equation (3) and equation (2) to eliminate b.
(4a−2b)+(3a+2b)=2+19
7a=21
Step 3: Solve for a.
a=721
a=3
Step 4: Substitute a=3 into equation (1).
2(3)−b=1
6−b=1
b=6−1
b=5
The solution is a=3,b=5.
3. (a)
Given the equations:
5p+2q=18(1)
p+2q=2(2)
Step 1: Subtract equation (2) from equation (1) to eliminate q.
(5p+2q)−(p+2q)=18−2
4p=16
Step 2: Solve for p.
p=416
p=4
Step 3: Substitute p=4 into equation (2).
4+2q=2
2q=2−4
2q=−2
Step 4: Solve for q.
q=2−2
q=−1
The solution is p=4,q=−1.
3. (b)
Given the equations:
3p+5k=30(1)
2p+3k=19(2)
Step 1: Multiply equation (1) by 2 and equation (2) by 3 to make the coefficients of p equal.
2(3p+5k)=2(30)⟹6p+10k=60(3)
3(2p+3k)=3(19)⟹6p+9k=57(4)
Step 2: Subtract equation (4) from equation (3) to eliminate p.
(6p+10k)−(6p+9k)=60−57
k=3
Step 3: Substitute k=3 into equation (1).
3p+5(3)=30
3p+15=30
3p=30−15
3p=15
Step 4: Solve for p.
p=315
p=5
The solution is p=5,k=3.
4. (a)
Given the equations:
4m+3n=28(1)
6m+2n=32(2)
Step 1: Multiply equation (1) by 3 and equation (2) by 2 to make the coefficients of m equal.
3(4m+3n)=3(28)⟹12m+9n=84(3)
2(6m+2n)=2(32)⟹12m+4n=64(4)
Step 2: Subtract equation (4) from equation (3) to eliminate m.
(12m+9n)−(12m+4n)=84−64
5n=20
Step 3: Solve for n.
n=520
n=4
Step 4: Substitute n=4 into equation (1).
4m+3(4)=28
4m+12=28
4m=28−12
4m=16
Step 5: Solve for m.
m=416
m=4
The solution is m=4,n=4.
4. (b)
Given the equations:
3x+5y=7(1)
4x+3y=2(2)
Step 1: Multiply equation (1) by 4 and equation (2) by 3 to make the coefficients of x equal.
4(3x+5y)=4(7)⟹12x+20y=28(3)
3(4x+3y)=3(2)⟹12x+9y=6(4)
Step 2: Subtract equation (4) from equation (3) to eliminate x.
(12x+20y)−(12x+9y)=28−6
11y=22
Step 3: Solve for y.
y=1122
y=2
Step 4: Substitute y=2 into equation (1).
3x+5(2)=7
3x+10=7
3x=7−10
3x=−3
Step 5: Solve for x.
x=3−3
x=−1
The solution is x=−1,y=2.
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