Solve the system of equations using substitution. y= 2x+3 y= 3x+1 a: (-2, -5) b: (-1, -2) c: (2, 7) d: (-2, -1)

50 points! antonio made a scale model of a building. the model's scale is 1 inch to 235 feet and its height is 3.5 inches. what is the exact height of the actual building? enter your answer in the box.

Complete the solution of the equation. find the value of y when x equals -5. -4x - 8y = -52

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?