The phrase "acted jointly" is correct and usable in written English.
It is typically used in legal or formal contexts to indicate that two or more parties are taking action together or in agreement.
Example: "The two companies acted jointly to develop a new product that would benefit both of their markets."
Alternatives: "collaborated together" or "worked in unison".
During the conflict between Lydia and the Medes, independent Cilicia and Babylonia, as two important nonaligned powers of the region, acted jointly as mediators.
States have acted jointly before, notably in the Reagan years, to force manufacturers of gasoline-powered vehicles into stricter tailpipe emission limits than Washington was demanding.
Islamic Jihad and a militia connected to Mr. Abbas's own Fatah faction, Al Aksa Martyrs Brigades, each claimed responsibility, and it appeared possible that they acted jointly.
The main area where they have acted jointly is in setting up the California Digital Library, which drives hard bargains with the publishers of periodicals to license the use of their electronic versions.
Unsurprisingly, the end result showed how the worlds most populous nation could easily trump others in a vote if its citizens acted jointly.
It seemed that the Ngn1 sequestration regulation and the Ngn1-miR-9 regulation acted jointly to warrant the neuronal cell fate specification.
Partners have to be ready to speak with each other and listen to each other -- but then to act jointly".
The US and Canada agreed to act jointly to cut methane emissions at a White House meeting in March.
Last week, he and Mr. Bush said they would act jointly to try to rein in all so-called 527 groups -- the unregulated committees purportedly independent of major-party campaigns -- on both sides of the partisan divide.
"But there is no doubt that the region as a whole is demonstrating an ability to act jointly and coherently, and that therefore a permanent Latin American presence on the Security Council is being seen from another perspective".
"The recent dramatic changes, from Syria to Ukraine and the Middle East to North Africa, require Turkey and the EU to act jointly against the global and regional threats," the government stresses.
