Hi there! To solve this, all we have to do is multiply each side by 2.2 to cancel out the variable and to find the value for it. 5.8 * 2.2 is 12.76. 12.76/2.2 is 5.8. x = 12.76. The answer is D.
In this case, the numbers would be 5*7 and 4*7 which is 35 and 28 respectively
im pretty sure the answer is 0.7
F(x) = 5x
for f(7) you replace x with 7 so it will be : f(7) = 5(7) = 35