Question

what is the value of k,if one root of the quadratic equation kx²-7x+12=0 is 3 ?​

Answer 1

Answer:

$kx ^{2} - 7x + 12 = 0 \\ let \: \: x = 3 \\ k(3) ^{2} - 7(3) + 12 = 0 \\ k(9) - 21 + 12 = 0 \\ 9k - 21 + 12 = 0 \\ 9k - 9 = 0 \\ 9k = 9 \\ k = 9 \div 9 \\ k = 1 \\ verification \\ k = 1 \\ kx ^{2} - 7x + 12 = 0 \\ 1(3) ^{2} - 7(3) + 12 = 0 \\ 9 - 21 + 12 = 0 \\ 21 - 21 = 0$

so k--1

i hope it's helps you if so please mark me as brilliant