Ex.4.3 Q4 Simple-Equations Solutions-Ncert Maths Class 7

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Question

(a) Construct $$3$$ equations starting with $$x = 2$$

(b) Construct $$3$$ equations starting with $$x=-2$$

Video Solution
Simple Equations
Ex 4.3 | Question 4

Text Solution

What is Known?

Value of the variables; $$x = 2$$ and $$x=-2$$

What is unknown?

$$3$$ equations starting with $$x = 2$$ and $$3$$ equations starting with $$x = 2$$

Reasoning:

You can get the equation by adding, multiplying or subtracting the same value on both sides of the equation.

Steps:

(a) $$3$$ equations starting with $$x = 2$$

(i) $$x = 2$$

Multiplying both sides by $$10$$,

$$10x = 20$$

Adding $$2$$ to both sides ,

\begin{align}10x + 2 &= 20 + 2\\10x + 2 &= 22\end{align}

(ii) $$x = 2$$

multiplying both sides by $$5$$,

$$5x = 10$$

subtracting $$3$$ to both sides,

\begin{align}5x - 3 &= 10 - 3\\5x - 3 &= 7\end{align}

(iii) $$x = 2$$

multiplying both sides by $$2$$,

$$2x = 4$$

subtracting $$3$$ to both sides,

\begin{align}2x - 3 &= 4 - 3\\2x - 3 &= 1\end{align}

(b) $$3$$ equations starting with $$x = -2$$

(i) $$x=-2$$

Multiplying both sides by $$3$$,

$$3x = - 6$$

(ii) $$x=-2$$

Multiplying both sides by $$3$$,

$$3x = - 6$$

Adding $$7$$ to both sides we get.

\begin{align}3x + 7 &= - 6 + 7\\ 3x + 7 &= 1\end{align}

(iii) $$x=-2$$

Multiplying both sides by $$3$$,

$$3x = - 6$$

Adding $$10$$ to both sides, we get.

\begin{align}3x + 10 &= - 6 + 10\\ 3x + 10& = 4\end{align}

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