Question

The cost of a chocolate is rs (x + 4) and rohit bought (x + 4) chocolates. Find the total amount paid by him in terms of x. If x = 10 and y =5, find the amount paid by him.

Answer 1

cost of the chocolate is rs(x+4)

chocolates bought by rohit is (x+4)

then the amount paid by him will be (x+4)(x+4)

since the value value of x is given as 10

so substituting 10 in the place of x

i.e (10+4)(10+4)=(14)(14)=196

Answer 2

Cost of one chocolate is Rs(x+4)

No. Of chocolates bought is (x+4) so total amount paid is (x+4)(x+4)=(x+4)^2_____which is total amount paid in terms of x

x^2+(4)^2+2*x*4=x^2+8x+16

It is a quadratic equation which can be solved by any method

Let's use factorisation to solve it.

(x^2+4x)+4x+16=0

x(x+4)+4(x+4)=0

(x+4)(x+4)=0

Thus x =4

So total amount paid =(x+4)^2

(4+4)^2= 8^2=64

So total amount paid =Rs64.

But if x=10

Total amount=(x+4)^2

(10+4)^2=(14)^2= Rs 196

There is no use of y in the question. So we don't need value of y

Hope it works