
Algebra Identities and Formulas
Last updated at Dec. 16, 2024 by Teachoo
Transcript
Question 8 Using (𝑥+𝑎)(𝑥+𝑏)=𝑥^2+(𝑎+𝑏)𝑥+𝑎𝑏 , find (iv) 9.7 × 9.8 9.7 ×9.8 = (10−0.3)×(10−0.2) = (10+(−0.3))×[10+(−0.2)] (𝑥+𝑎)(𝑥+𝑏)=𝑥^2+(𝑎+𝑏)𝑥+𝑎𝑏 Putting 𝑥 = 10 , 𝑎 = −0.3 & 𝑏 = −0.2 = (10)^2+(−0.3−0.2)(10)+(−0.3)(−0.2) = 100+(−0.5×10)+(0.3×0.2) = 100−(5/10×10)+(3/10×2/10) = 100−5+6/100 = 95+0.06 = 𝟗𝟓.𝟎𝟔