Solve the system of equations by substitution method: y + 2 = 3x 7x + 2y = 9

y + 2 = 3x; 7x + 2y = 9 – from the first equation we express y through x;

y = 3x – 2 – substitute the expression (3x – 2) instead of y in the second equation;

7x + 2 (3x – 2) = 9;

7x + 6x – 4 = 9;

13x = 9 + 4;

13x = 13;

x = 13: 13;

x = 1 – find y, substituting for y the number 1 in y = 3x – 2;

y = 3 * 1 – 2 = 3 – 2 = 1.

Answer. (eleven).