7×3=(_×3)+(4×3)= what is the missing number and answe

3 is the missing answer.

Step-by-step explanation:

7 * 3 = ( _ * 3) + ( 4 * 3)

21 = ( _ * 3) + 12              -Multiply 4 * 3 and 7 * 3

9 = _ * 3                          -Divide both sides by 3

3 = missing number

= 5

step-by-step explanation:

to find the 15th term substitute n = 15 into the nth term formula

= (- 3 × 15 ) + 50 = - 45 + 50 = 5