👉🏼 What is 21 ÷ -7 (without a calculator)

👈🏼 A television is sold in the sales with a 20% discount.
In the sales, the it is sold for £99.20
What is the usual price of the television?

👆🏼 Estimate

👇🏼 Calculate the value of x in the triangle below:

🖐🏼 Make x the subject of y = 2(y+5x)³