Question

2 Dora has solved the equation 4(x - 1) = 11

4(x - 1) = 11
4x41 = 11
4x = 52
x = 13
Dora is incorrect. Explain her mistake.
Dora put the x es
and did 4x11
11 and
Find the correct solution to 4(x − 1) = 11
I mark

Answer 1

Dora solved the equation.

She multiplies 4 inside the bracket. But she fails to know that 4× -1 = -4. Instead she multiplied that 4×-1 = -41. This is her first mistake.

In the second step, she shifted -41 to the right side in order to find the value of x. As -41 gets shifted to right side , -41 becomes +41 and added with +11 to get 52. which is totally a wrong method.

Explanation:

Here is the exact method of solvation.

`{ \blue{ \bold{4(x - 1) = 11}}}`

`{ \blue{ \bold{4x - 4 = 11}}}`

`{ \blue{ \bold{4x = 11 + 4}}}`

`{ \blue{ \bold{4x = 15}}}`

`{ \blue{ \boxed{ \red{ \sf{x = (15)/(4)}}}}}`