Why does the inequality sign have to be flipped when multiplying and dividing by a negative number like in −2x > 10?
1 answer:
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The college student took 13 courses of 3 credit hours.
Step-by-step explanation:
Given,
Total credits = 59
Total courses = 18
Let,
Number of 3 credit hour courses = x
Number of 4 credit hour courses = y
According to given statement;
x+y=18 Eqn 1
3x+4y=59 Eqn 2
We will eliminate y to find the number of 3 credit hour courses, therefore,
Multiplying Eqn 1 by 4
Subtracting Eqn 2 from Eqn 3
The college student took 13 courses of 3 credit hours.
Keywords: linear equation, subtraction
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We know the area formula of a triangle
We are given:
The area = 56 m²
The base = let p represent this
The height = 9 m less than the base = p - 9
Apply the formula
56 =
× ( p ) × ( p - 9 )
56 = × ( p² - 9p )
Divide on both sides
56 ÷ = p² - 9p
112 = p² - 9p
Bring 112 to the other side and equate equation to 0
p² - 9p - 112
Factorise { Sum = -9 , Product = - 112 , therefore suitable factors = - 16 × 7 )
( p - 16 )( p + 7 ) = 0
↓ ↓
p = 16 p = - 7 ← Reject p = - 7 since length cannot be negative
So, the length of the base is 16 m
Check:
56 m² = × 16 × ( 16 - 9 )
56 m² = 8 × 7
56 m² = 56 m²
We know the area formula of a triangle
We are given:
The area = 56 m²
The base = let p represent this
The height = 9 m less than the base = p - 9
Apply the formula
56 =
56 =
Divide
56 ÷
112 = p² - 9p
Bring 112 to the other side and equate equation to 0
p² - 9p - 112
Factorise { Sum = -9 , Product = - 112 , therefore suitable factors = - 16 × 7 )
( p - 16 )( p + 7 ) = 0
↓ ↓
p = 16 p = - 7 ← Reject p = - 7 since length cannot be negative
So, the length of the base is 16 m
Check:
56 m² =
56 m² = 8 × 7
56 m² = 56 m²