Answer:
![\boxed{ \boxed{ \mathrm{ \bold{ \blue{ - 10}}}}}](https://img.qammunity.org/2021/formulas/mathematics/high-school/7x3p49s84s0tc4fdd65lbxu4cuues478ne.png)
Explanation:
![\mathrm{ - 22 = - 8u + 6(u - 7)}](https://img.qammunity.org/2021/formulas/mathematics/high-school/oq8eensjtlgy1rjnbro5hrow5l71wtgcdx.png)
Distribute 6 through the parentheses
⇒
![\mathsf{ - 22 = -8u + 6u - 42}](https://img.qammunity.org/2021/formulas/mathematics/high-school/82fyinam8x8ykxn2n5yo7xv7aa1psmmu90.png)
Collect like terms
⇒
![\mathrm{ - 22 = - 2u - 42}](https://img.qammunity.org/2021/formulas/mathematics/high-school/xdoyybcbqsu436fqmp9rkmold5w5dz127r.png)
Swap the sides of the equation
⇒
![\mathrm{ -2u - 42 = - 22}](https://img.qammunity.org/2021/formulas/mathematics/high-school/5t4lqp30ucztxk2arsnr7zhezuxs87frd6.png)
Move constant to R.H.S and change it's sign
⇒
![\mathrm{ - 2u = - 22 + 42}](https://img.qammunity.org/2021/formulas/mathematics/high-school/pun30m3y6qw4tn7zdzwrg40uzm5b0n9ivw.png)
Calculate
⇒
![\mathrm{ - 2u = 20}](https://img.qammunity.org/2021/formulas/mathematics/high-school/jm101aoitkuqexy38n5110ovvv9g9zfz7z.png)
Divide both sides of the equation by -2
⇒
![\mathrm{ ( - 2u)/( - 2) = (20)/( - 2) }](https://img.qammunity.org/2021/formulas/mathematics/high-school/ou7r6qx6z5xrg0onu4icfuc55wa05vj4a6.png)
Calculate
⇒
![\mathrm{u = - 10}](https://img.qammunity.org/2021/formulas/mathematics/high-school/3wgw9re5o7ta04qk1d7q87vewknpx8fabb.png)
Hope I helped!
Best regards!