Write 5 equations whose solution is x = - 2. Class 7

Write 5 equations whose solution is x = - 2. Class 7

Question 1.

Write 5 equations whose solution is x = - 2.

Solution:

2x = - 4; 4x = -8; 7x = - 14; 5x = -10; -6x = 12.

Question 2.

Find the value of each unknown:

(a) 2y = 60

Solution:

y = [latex]\frac {60}{2}[/latex] = 30

(b) - 8 = 5x - 3

Solution:

-8 = 5x - 3. So, 5x = -8 + 3.

or 5x = - 5 or x = [latex]\frac {-5}{5}[/latex] = -1.

(c) - 53m = -15

Solution:

[latex]\frac {1}{2}[/latex]

(d) 13 - 2 = 8

Solution:

13 - 2 = 8 or z = 13 - 8 = 5.

(e) k + 8 = 12 - k

Solution:

k + 8 = 12 - k or k + k = 12 + 8

or 2k = 4, i.e., k = [latex]\frac {4}{2}[/latex] = 2.

(f) 7m = m - 3

Solution:

7m = m - 3 or 7m - m = 3

or 6m = - 3, i.e., m = -[latex]\frac {3}{6}[/latex] = -[latex]\frac {1}{2}[/latex].

(g) 3n = 10 + n

Solution:

3n = 10 + n or 3n - n = 10.

or 2n = 10 i.e., n = [latex]\frac {10}{2}[/latex] = 5.

Question 3.

I am a 3-digit number. My hundred’s digit is 3 less than my ten’s digit. My ten’s digit is 3 less than my unit’s digit. The sum of all the three digits is 15. Who am I? Class 7

Solution:

Let unit’s digit be x. So, ten’s digit = x - 3 and hundred’s digit = x - 3 - 3 = x - 6.

So, = x+ x - 3 + x - 6 = 15.

or 3x - 9 = 15

or 3x = 15 + 9

or 3x = 24

or x = [latex]\frac {24}{3}[/latex] =8.

So, the number is 258.