If 2x + 3y = 17 and 3x + 4y = 24, then what is 5x +7y?

Question

3410 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-05-09T04:37:42

$color(indigo)(5x + 7y = (5 * 4) + (7 * 3) = 41$

$2x + 3y = 17, " Eqn (1)"$

$6x + 9y = 51, color(red)(" Eqn (3) = 3 * Eqn (1)"$

$3x + 4y = 24, " Eqn (2)"$

$6x + 8y = 48, color(red)(" Eqn (4) = 2 * Eqn (2)"$

$6x - 6x + 9y - 8y = 51 - 48, color(purple)(" Eqn (3) - Eqn (4)"$

$y = 3$

Substituting value of y in eqn 91),

$2x + 9 = 17$

$2x = 8, x = 4$

$color(indigo)(5x + 7y = (5 * 4) + (7 * 3) = 41$