11) -x + y = -1 ; 2x - y = 0
y = -1 + x ; 2x - (-1+x) = 0 ⇒ 2x + 1 - x = 0 ⇒x = -1
y = -1 + (-1) ⇒ y = -2
12) -2x + y = -20 ; 2x + y = 48
y = -20 + 2x ; 2x + (-20 + 2x) = 48 ⇒ 2x -20 + 2x = 48 ⇒ 4x = 48 + 20
4x = 68 ⇒ x = 68/4 ⇒ x = 17
y = -20 + 2(17) ⇒ y = -20 + 34 ⇒ y = 14
13) 3x -y = -2 ; -2x + y = 3
y = 3 + 2x ; 3x - (3 + 2x) = -2 ⇒ 3x - 3 - 2x = -2 ⇒ x = -2 + 3 ⇒ x = 1
y = 3 + 2(1) ⇒ y = 3 + 2 ⇒ y = 5
14) x - y = 4 ; x - 2y = 10
x = 4 + y ; (4 + y) - 2y = 10 ⇒ 4 + y - 2y = 10 ⇒ 4 - y = 10
⇒ -y = 10 - 4 ⇒ -y = 6 ⇒ y = -6
x = 4 + (-6) ⇒ x = 4 - 6 ⇒ x = -2
15) x + 2y = 5 ; 3x + 2y = 17
x = 5 - 2y ; 3(5-2y) + 2y = 17 ⇒ 15 - 6y + 2y = 17 ⇒ -4y = 17 - 15
⇒ -4y = 2 ⇒ y = -2/4 ⇒ y = -1/2
x = 5 - 2(-1/2) ⇒ x = 5 + 2/2 ⇒ x = 5 + 1 ⇒ x = 6
0.46
Step-by-step explanation:
23÷50= 0.46
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Answer:
See Explanation
Step-by-step explanation:
a) Additive inverse of −2
- the additive inverse of a number a is the number that, when added to 'a', yields zero. This number is also known as the opposite (number), sign change, and negation.
- So the Additive inverse of -2 is 2. ∴ -2+2=0
b) Additive identity of −5
- Additive identity is the value when added to a number, results in the original number. When we add 0 to any real number, we get the same real number.
- -5 + 0 = -5. Therefore, 0 is the additive identity of any real number.
c) additive inverse of 3
- Two numbers are additive inverses if they add to give a sum of zero. 3 and -3 are additive inverses since 3 + (-3) = 0. -3 is the additive inverse of 3.
d). multiplicative identity of 19
- an identity element (such as 1 in the group of rational numbers without 0) that in a given mathematical system leaves unchanged any element by which it is multiplied
- Multiplicative identity if 19 is 1 only, since 19 x 1 = 19.
e) multiplicative inverse of 7
- Dividing by a number is equivalent to multiplying by the reciprocal of the number. Thus, 7 ÷7=7 × 1⁄7 =1. Here, 1⁄7 is called the multiplicative inverse of 7.
d) | 11-5|×|1-5|
- | 11-5|×|1-5| ⇒ I6I×I-4I ⇒ 6×4 ⇒ 24
