Tolong bantuin ya makasih

Tolong bantuin ya makasih

Simple Algebraic Equation

A simple algebraic equation contains a single variable (usually written as "x" or any alphabetic word)

1. Q: The sum of 20 and twice an unknown number is 70. The unknown number is…

Answer:

Let the unknown number as "x". So, we can write the equation based on the problem:

$boxed{20 + 2x = 70}$

Find the value of "x" using algebraic operation

$20 + 2x = 70\2x = 70 - 20\2x = 50\x = 25$

Hence, the value of the unknown number is 25

2. Q: A string of length 120 cm is cut into 2 pieces. One piece is 30 cm shorter than the other. The length of the longer piece is

Answer:

Let the longer piece as "x". So, we can write the equation based on the problem:

$boxed{120 = x + (x - 30)}$

Find the value of "x" using algebraic operation

$120 = x + x - 30\120 = 2x - 30\120 + 30 = 2x\150 = 2x\x = 75$

Hence the length of the other piece is 75 cm

3. Q: In a bus of 54 passengers, the number of adults is 5 times the number of children. Find the number of the adults

Answer:

Let the number of children as "x". So, we can write the equation based on the problem:

$boxed{54 = x + 5x}$

Find the value of "x" using algebraic operation

$54 = x + 5x\54 = 6x\x = 9$

The number of children is 9. Hence, there are 45 adults (from 9 × 5)

4. Q: Wire A is w m long. Wire B is twice as long as Wire A. Wire C is 3 m shorter than Wire B. If the total length of the three wires is 32 m, how long is Wire A?

Answer:

Let the length of wire A as "w", So..

A = w m

B = 2w m

C = 2w – 3 m

*) m stand for "meter"

So, we can write the equation based on the problem

$boxed{32 = w + 2w + (2w - 3)}$

To find the value of "w", use algebraic operation

$32 = w + 2w + (2w - 3)\32 = 3w + (2w - 3)\32 = 3w + 2w - 3\32 = 5w - 3\32 + 3 = 5w\35 = 5w\w = 7$

Hence, the length of wire A is 7 meter

5. Q: There are x people on the train. At the next station, 37 people get off and 12 people get on. How many people are on the train now in terms of x?

Answer:

Let the people on the train as "x", so the equation to find the amount of people on that problem is

$x - 37 + 12\x - 25$

Hence, there are x – 25 people onboard right now

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Details:

Subjects: Mathematics

Topic: Algebra