某数的4倍加0.9乘3的积,和是6.7,求这个数

设这个数为x .
4x + 0.9 × 3 = 6.7
4x + 2.7 = 6.7
4x = 6.7 - 2.7
4x = 4
x = 4 ÷ 4
x = 1