Solve 5a−a3=3 for a. a=103−1069,a=103+1069Substitute 103−1069 for a in 7b−1=a−21 and solve.7b−17bb=−10207−1069=−10197−1069=−70197−7069This yields the following solution. a=103−1069,b=−70197−7069Substitute 103−1069 for a in 7b−1=a−21 and simplify. 7b−17b−1b=a−21=(103−1069)−21=−70197−7069Substitute −70197−7069 into 7b−1=a−21 to solve for a. −10207−1069−aa=a−21=−103+1069=103−1069This yields the following solutions. a=103−1069,b=−70197−7069Substitute 103+1069 for a in 7b−1=a−21 and solve.7b−17bb=−10207+1069=−10197+1069=−70197+7069This yields the following solution. a=103+1069,b=−70197+7069