Final answer:
To solve for x in the equation 21x+5=40°, divide both sides by 21 to find the value of x. Then, substitute the value of x into the equation 13x+5 to find its value.
Step-by-step explanation:
To solve for x in the equation 21x+5=40°, we need to isolate x on one side of the equation. Step 1: Subtract 5 from both sides, which gives 21x = 35°. Step 2: Divide both sides by 21 to find the value of x, which is x = 35°/21 = 5/3°. Therefore, the solution to the equation is x = 5/3°.
To find the value of 13x+5, we substitute the value of x we found (5/3°) into the equation. So, 13(5/3°)+5 = 65/3° + 5 = (65 + 15)/3° = 80/3°. Therefore, the value of 13x+5 is 80/3°.