Here are the solutions for the remaining problems in .3.
1. Add the following expressions:
1.7 5m2−4mn+7n2; −10n2+mn; 7m2−10n2
Step 1: Group like terms.
(5m2+7m2)+(−4mn+mn)+(7n2−10n2−10n2)
Step 2: Combine like terms.
12m2−3mn−13n2
The sum is ∗12m2−3mn−13n2∗.
1.8 −3x2+3xy−y2; −4x2−7xy−10y2; −3xy+15y2
Step 1: Group like terms.
(−3x2−4x2)+(3xy−7xy−3xy)+(−y2−10y2+15y2)
Step 2: Combine like terms.
−7x2−7xy+4y2
The sum is ∗−7x2−7xy+4y2∗.
1.9 5a2b−4ab2+2ab; 10a2b+ab2−ab; −6a2b−2ab2−3ab
Step 1: Group like terms.
(5a2b+10a2b−6a2b)+(−4ab2+ab2−2ab2)+(2ab−ab−3ab)
Step 2: Combine like terms.
9a2b−5ab2−2ab
The sum is ∗9a2b−5ab2−2ab∗.
1.10 8x3+6x2−4x+5; −x3−2x2+3x−7
Step 1: Group like terms.
(8x3−x3)+(6x2−2x2)+(−4x+3x)+(5−7)
Step 2: Combine like terms.
7x3+4x2−x−2
The sum is ∗7x3+4x2−x−2∗.
2. Subtract the second expression from the first expression:
2.1 3a+7; 5a−3
Step 1: Write the subtraction.
(3a+7)−(5a−3)
Step 2: Distribute the negative sign and group like terms.
3a+7−5a+3=(3a−5a)+(7+3)
Step 3: Combine like terms.
−2a+10
The difference is ∗−2a+10∗.
2.2 5x+2y; −9x+2y
Step 1: Write the subtraction.
(5x+2y)−(−9x+2y)
Step 2: Distribute the negative sign and group like terms.
5x+2y+9x−2y=(5x+9x)+(2y−2y)
Step 3: Combine like terms.
14x+0y=14x
The difference is ∗14x∗.
2.3 3b−9; 7−2b
Step 1: Write the subtraction.
(3b−9)−(7−2b)
Step 2: Distribute the negative sign and group like terms.
3b−9−7+2b=(3b+2b)+(−9−7)
Step 3: Combine like terms.
5b−16
The difference is ∗5b−16∗.
2.4 1; 8k+4
Step 1: Write the subtraction.
(1)−(8k+4)
Step 2: Distribute the negative sign and group like terms.
1−8k−4=−8k+(1−4)
Step 3: Combine like terms.
−8k−3
The difference is ∗−8k−3∗.
2.5 4a+b−2c; −a+3b+c
Step 1: Write the subtraction.
(4a+b−2c)−(−a+3b+c)
Step 2: Distribute the negative sign and group like terms.
4a+b−2c+a−3b−c=(4a+a)+(b−3b)+(−2c−c)
Step 3: Combine like terms.
5a−2b−3c
The difference is ∗5a−2b−3c∗.
2.6 3x2+4x−1; −2x2−3x+5
Step 1: Write the subtraction.
(3x2+4x−1)−(−2x2−3x+5)
Step 2: Distribute the negative sign and group like terms.
3x2+4x−1+2x2+3x−5=(3x2+2x2)+(4x+3x)+(−1−5)
Step 3: Combine like terms.
5x2+7x−6
The difference is ∗5x2+7x−6∗.
2.7 2a2−ab+b2; 2a2+ab−b2
Step 1: Write the subtraction.
(2a2−ab+b2)−(2a2+ab−b2)
Step 2: Distribute the negative sign and group like terms.
2a2−ab+b2−2a2−ab+b2=(2a2−2a2)+(−ab−ab)+(b2+b2)
Step 3: Combine like terms.
0a2−2ab+2b2=−2ab+2b2
The difference is ∗−2ab+2b2∗.
2.8 5m2+3mn−5n2; −5m2+8mn
Step 1: Write the subtraction.
(5m2+3mn−5n2)−(−5m2+8mn)
Step 2: Distribute the negative sign and group like terms.
5m2+3mn−5n2+5m2−8mn=(5m2+5m2)+(3mn−8mn)−5n2
Step 3: Combine like terms.
10m2−5mn−5n2
The difference is ∗10m2−5mn−5n2∗.
2.9 2a2b−4ab2+ab; −2a2b−4ab2+ab
Step 1: Write the subtraction.
(2a2b−4ab2+ab)−(−2a2b−4ab2+ab)
Step 2: Distribute the negative sign and group like terms.
2a2b−4ab2+ab+2a2b+4ab2−ab=(2a2b+2a2b)+(−4ab2+4ab2)+(ab−ab)
Step 3: Combine like terms.
4a2b+0ab2+0ab=4a2b
The difference is ∗4a2b∗.
2.10 4y3−7y2+2y−1; −y3+3y2+y−3
Step 1: Write the subtraction.
(4y3−7y2+2y−1)−(−y3+3y2+y−3)
Step 2: Distribute the negative sign and group like terms.
4y3−7y2+2y−1+y3−3y2−y+3=(4y3+y3)+(−7y2−3y2)+(2y−y)+(−1+3)
Step 3: Combine like terms.
5y3−10y2+y+2
The difference is ∗5y3−10y2+y+2∗.
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