How do you solve the x-4y=22
2x+5y=-21 using substitution? ? someone

The function a represents the cost of manufacturing product a, in hundreds of dollars, and the function b represents the cost of manufacturing product b, in hundreds of dollars. a(t) = 5t + 2 b(t) = 7t - 2t +4 find the expression that describes the total cost of manufacturing both products, a(t) + b(t). a. 7t^2 - 7t + 2 b. 7t^2 + 3 +6 c. 7t^2 + 7t - 6 d. 7t^2 - 3t + 6

What is the value of x in the equation 2(x-4) = 4(2x + 1)?

The table represents a function. what is f(-2)? a.-3 b. -1 c.1 d.3