The World of Numbers | Exercise 3.3

Question 8

Find the rational number xx such that:

56(x+35)=56x+12\frac{5}{6}\left(x + \frac{3}{5}\right) = \frac{5}{6}x + \frac{1}{2}

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Solution

We need to find the value of xx that makes the equation true.

Step 1 — Simplify the left side

Let's start by expanding the left side of the equation. We will use the distributive property. 56(x+35)=56x+56×35\frac{5}{6}\left(x + \frac{3}{5}\right) = \frac{5}{6}x + \frac{5}{6} \times \frac{3}{5}

Now, let's multiply the fractions. =56x+5×36×5= \frac{5}{6}x + \frac{5 \times 3}{6 \times 5}

We can simplify the product of fractions. =56x+1530= \frac{5}{6}x + \frac{15}{30}

Let's reduce the fraction 1530\frac{15}{30}. =56x+12= \frac{5}{6}x + \frac{1}{2}

LHS=56x+12\boxed{\text{LHS} = \frac{5}{6}x + \frac{1}{2}}

Step 2 — Compare both sides

Now we substitute the simplified left side back into the equation. The original equation was 56(x+35)=56x+12\frac{5}{6}\left(x + \frac{3}{5}\right) = \frac{5}{6}x + \frac{1}{2}. After simplifying, the equation becomes: 56x+12=56x+12\frac{5}{6}x + \frac{1}{2} = \frac{5}{6}x + \frac{1}{2}

Let's move all terms with xx to one side. We will subtract 56x\frac{5}{6}x from both sides. 56x+1256x=56x+1256x\frac{5}{6}x + \frac{1}{2} - \frac{5}{6}x = \frac{5}{6}x + \frac{1}{2} - \frac{5}{6}x

This simplifies to: 12=12\frac{1}{2} = \frac{1}{2}

The equation simplifies to 12=12\boxed{\text{The equation simplifies to } \frac{1}{2} = \frac{1}{2}}

Step 3 — Determine the value of x

The simplified equation 12=12\frac{1}{2} = \frac{1}{2} is always true. There is no xx left in the equation. This means the equation holds for any value of xx. Since we are looking for a rational number xx. Any rational number will satisfy this equation.

Answer

The rational number xx can be any rational number.

More questions in Exercise 3.3

Q1

Prove that the following rational numbers are equal:

(i) 23\frac{2}{3} and 46\frac{4}{6} (ii) 54\frac{5}{4} and 108\frac{10}{8} (iii) 35-\frac{3}{5} and 610-\frac{6}{10} (iv) 93\frac{9}{3} and 33

Q2

Find the sum:

(i) 25+310\frac{2}{5} + \frac{3}{10} (ii) 712+58\frac{7}{12} + \frac{5}{8} (iii) 47+314-\frac{4}{7} + \frac{3}{14}

Q3

Find the difference:

(i) 5614\frac{5}{6} - \frac{1}{4} (ii) 11834\frac{11}{8} - \frac{3}{4} (iii) 79(23)-\frac{7}{9} - \left(-\frac{2}{3}\right)

Q4

Find the product:

(i) 23×310\frac{2}{3} \times \frac{3}{10} (ii) 711×58\frac{7}{11} \times \frac{5}{8} (iii) 47×514-\frac{4}{7} \times \frac{5}{14}

Q5

Find the quotient:

(i) 23÷310\frac{2}{3} \div \frac{3}{10} (ii) 711÷58\frac{7}{11} \div \frac{5}{8} (iii) 47÷514-\frac{4}{7} \div \frac{5}{14}

Q6

Show that:

(12+34)×83=12×83+34×83\left(\frac{1}{2} + \frac{3}{4}\right) \times \frac{8}{3} = \frac{1}{2} \times \frac{8}{3} + \frac{3}{4} \times \frac{8}{3}

Q7

Simplify the following using the distributive property:

79(6734)\frac{7}{9}\left(\frac{6}{7} - \frac{3}{4}\right)

Q8

Find the rational number xx such that:

56(x+35)=56x+12\frac{5}{6}\left(x + \frac{3}{5}\right) = \frac{5}{6}x + \frac{1}{2}

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