15. Find the value of the expressions using identities.(a) 25x2 + 70x – InterviewSolution

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1.	15. Find the value of the expressions using identities.(a) 25x2 + 70x + 49 if x = -1(b) 49X2 – 84xy + 36y2 if x = 2, y = 3
Answer» 15) a) 25x^2+70x+49; x=-1; =25(-1)^2+70(-1)+49= =25-70+49=74-70=4; b) 49x^2-84xy+36y^2; x=2, y=3; 49(2)^2-84(2)(3)+36(3)^2 =49(4)-84(6)+36(9) =196-504+324=520-504=16

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