Question

Can someone help me PLEASE

Answer 1

Let's solve this problem step-by-step:

   $7 * 9 = (7*10)-(7*x)$

• x: it is the delta in the equation given in your picture

We know (7*10) - (7*x) is equivalent to the 7*(10-x)

 ⇒ based on the Distributive Properties

                           $a*(b+c) = ab + ac$  

          $7*(10+(-x))=(7*10)+(7*(-x)=(7*10)-(7*x)$

 So:

   $7*9=7(10-x)\\9=10-x\\x=10-9\\x= 1$

Thus delta (the little triangle in this problem) in this case is 1

Answer: 1

Hope that helps!