A person while calculating the correlation coefficient between the variables X and y Obtained the following n=30, Ex=120 Ex^2=600, ey=90, Ey² =250, Exy=256. It was however lates discovered at the time of checking that it had copied down two pass of observation as (8,10) and (12,7) while correct values were (8,12) and (10,8) obtain the correct value of Correlation coefficient between them.​

When you answer this can you explain

Ten times the square of a non-zero number is eqaul to ninety times the number

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.