Answer:
Equation that can be used = [tex]\frac{4(88)+2x}{6} = 90[/tex]
Step-by-step explanation:
Given that:
Amir's average on four tests = 88
Let,
x be the score on one test
For two tests = 2x
Sum of all scores = Average of four tests + Score of two tests
Sum of all scores = 4(88) + 2x
Total number of tests = 6
Overall average needed = 90
Now,
[tex]Average = \frac{Sum\ of\ quantities}{Number\ of\ quantities}\\90 = \frac{4(88)+2x}{6}\\\\\frac{4(88)+2x}{6} = 90[/tex]
Hence,
Equation that can be used = [tex]\frac{4(88)+2x}{6} = 90[/tex]
