How is the mathematical calculation done in this step? The value of 2 / 4 of (2Y's square + 3Y + 7) is 1 / 4 ｛ 2Y & ｛ 178; + 3Y + 7 = 8 The value of 2 / 2 of (2Y + 3Y + 7) is one fourth ∴2y²+3y+7=8 Why is it equal to eight?

The left and right of this equation are fractions, which can be calculated by the method of cross multiplication. Multiplying the lower left by the upper right equals to multiplying the upper left by the lower right. Then we can get the answer

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