Question

${y}^{2} - 21y + 90$
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Answer 1

Answer:

it is quadratic equation ..........

Answer 2

Answer:

y² - 21 + 90

= y² - (15 + 6) y + 90

= y² - 15y - 6y + 90

= y( y - 15 ) - 6( y - 15)

= ( y - 15 ) ( y - 6 )