6,3x-4-3*(72x+0.3) решение? при x =2/3

6.3х-4-3*(72х+0.3) = 6.3х + (-4)+(-216х)+(-0.9)=(6.3х+(-2.16х))+(-4+(-9))=-209.7х + (-4.9)
т.к. х= 2/3, то
-209.7 * 2/3 + (-4.9)= -139.8 - 4.9 = -144.7