If x = 1; y = 2 find the values of the following expressions(i) 4x –

1.	If x = 1; y = 2 find the values of the following expressions(i) 4x – 3y + 5(ii) x2 + y2(iii) xy + 3y – 9
Answer» i) 4x – 3y+5 If x = 1, y = 2 then the value of 4x – 3y + 5 = 4(1) – 3(2) + 5 = 4 – 6 + 5 = 9 – 6 = 3 ii) x² + y² If x = 1, y = 2, the value of x² + y²= (1)² + (2)² =(1 × 1) + (2 × 2) = 5 iii) xy + 3y – 9 If x = 1; y = 2,the value of xy + 3y – 9 = 1 × 2 + 3(2) – 9 = 2 + 6 – 9 = 8 – 9

If x = 1; y = 2 find the values of the following expressions(i) 4x – 3y + 5(ii) x2 + y2(iii) xy + 3y – 9

Answer»

i) 4x – 3y+5

If x = 1, y = 2 then the value of 4x – 3y + 5

= 4(1) – 3(2) + 5

= 4 – 6 + 5

= 9 – 6 = 3

ii) x² + y²

If x = 1, y = 2, the value of x² + y²= (1)² + (2)²
=(1 × 1) + (2 × 2)
= 5

iii) xy + 3y – 9

If x = 1; y = 2,the value of xy + 3y – 9

= 1 × 2 + 3(2) – 9

= 2 + 6 – 9

= 8 – 9